Does A/C encourage mold growth












15














I think i'm being sold bunk by a mold company, but not sure.



We live in the tropics, we recently had our bathroom ceiling flood due to a burst pipe, and went away immediately after. (the landlord had the bathroom ceiling removed a bit under a week into our holiday)



Before we left, we called a mold control company and said we were going to leave the A/C on to keep the humidity down to prevent mold growth (we have a new A/C, very efficient, was going to keep it on the lowest setting just to dry the air a bit, so the energy usage would not have been a concern). They said not to do that. They're the "experts" so we followed their advice.



When we returned, the apartment had bloomed (literally bloomed) with mold.



Our landlord now is saying that this is because we use the A/C a lot (we don't), and need to open the unit windows more, and buy a dehumidifier. If we actually did use the A/C a lot, wouldn't the cooling and drying of the air have prevented the mold growth more than opening the unit?



We live next to a rainforest, so I would've thought that opening the unit would invite spores and damp air in rather than prevent mold?



Thanks in advance for any help






air-conditioning mold humidity







share|improve this question















migrated from mechanics.stackexchange.com yesterday


This question came from our site for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles.











  • 3




    Odd that both parties would give you that flawed advice. I'm guessing that you don't pay utilities separately from your rent, giving the owner motivation to discourage AC use.
    – isherwood
    yesterday






  • 3




    There's one circumstance where I could see it being an issue -- if you run the AC aggressively during the day and cool down the house to, say 65 degrees, and then at night you open the windows and let warm moist 85 degree air in, it could cause condensation on walls and other surfaces.
    – Johnny
    yesterday








  • 5




    "and buy a dehumidifier" A/C is a dehumidifier.
    – Acccumulation
    yesterday






  • 2




    The lease contract places onus for repairs above $150 on the landlord - the mold outbreak occurred after slow repair of the waterlogged roof, so the landlord is incentivised to blame us for the mold. The A/Cs are about a month old, so unlikely they are the source of the mould
    – ChristopherJ
    17 hours ago






  • 2




    @JimmyJames Well, those in e.g. office buildings and hotels almost always have but a lot of newer systems for home use have a fresh air intake as well. It allows you to filter out pollen and pollution from the outside air for example. You can also pre-cool the intake air by routing it through the ground to increase efficiency.
    – Christian
    11 hours ago
















15














I think i'm being sold bunk by a mold company, but not sure.



We live in the tropics, we recently had our bathroom ceiling flood due to a burst pipe, and went away immediately after. (the landlord had the bathroom ceiling removed a bit under a week into our holiday)



Before we left, we called a mold control company and said we were going to leave the A/C on to keep the humidity down to prevent mold growth (we have a new A/C, very efficient, was going to keep it on the lowest setting just to dry the air a bit, so the energy usage would not have been a concern). They said not to do that. They're the "experts" so we followed their advice.



When we returned, the apartment had bloomed (literally bloomed) with mold.



Our landlord now is saying that this is because we use the A/C a lot (we don't), and need to open the unit windows more, and buy a dehumidifier. If we actually did use the A/C a lot, wouldn't the cooling and drying of the air have prevented the mold growth more than opening the unit?



We live next to a rainforest, so I would've thought that opening the unit would invite spores and damp air in rather than prevent mold?



Thanks in advance for any help






air-conditioning mold humidity







share|improve this question















migrated from mechanics.stackexchange.com yesterday


This question came from our site for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles.











  • 3




    Odd that both parties would give you that flawed advice. I'm guessing that you don't pay utilities separately from your rent, giving the owner motivation to discourage AC use.
    – isherwood
    yesterday






  • 3




    There's one circumstance where I could see it being an issue -- if you run the AC aggressively during the day and cool down the house to, say 65 degrees, and then at night you open the windows and let warm moist 85 degree air in, it could cause condensation on walls and other surfaces.
    – Johnny
    yesterday








  • 5




    "and buy a dehumidifier" A/C is a dehumidifier.
    – Acccumulation
    yesterday






  • 2




    The lease contract places onus for repairs above $150 on the landlord - the mold outbreak occurred after slow repair of the waterlogged roof, so the landlord is incentivised to blame us for the mold. The A/Cs are about a month old, so unlikely they are the source of the mould
    – ChristopherJ
    17 hours ago






  • 2




    @JimmyJames Well, those in e.g. office buildings and hotels almost always have but a lot of newer systems for home use have a fresh air intake as well. It allows you to filter out pollen and pollution from the outside air for example. You can also pre-cool the intake air by routing it through the ground to increase efficiency.
    – Christian
    11 hours ago














15












15








15


2





I think i'm being sold bunk by a mold company, but not sure.



We live in the tropics, we recently had our bathroom ceiling flood due to a burst pipe, and went away immediately after. (the landlord had the bathroom ceiling removed a bit under a week into our holiday)



Before we left, we called a mold control company and said we were going to leave the A/C on to keep the humidity down to prevent mold growth (we have a new A/C, very efficient, was going to keep it on the lowest setting just to dry the air a bit, so the energy usage would not have been a concern). They said not to do that. They're the "experts" so we followed their advice.



When we returned, the apartment had bloomed (literally bloomed) with mold.



Our landlord now is saying that this is because we use the A/C a lot (we don't), and need to open the unit windows more, and buy a dehumidifier. If we actually did use the A/C a lot, wouldn't the cooling and drying of the air have prevented the mold growth more than opening the unit?



We live next to a rainforest, so I would've thought that opening the unit would invite spores and damp air in rather than prevent mold?



Thanks in advance for any help






air-conditioning mold humidity







share|improve this question















I think i'm being sold bunk by a mold company, but not sure.



We live in the tropics, we recently had our bathroom ceiling flood due to a burst pipe, and went away immediately after. (the landlord had the bathroom ceiling removed a bit under a week into our holiday)



Before we left, we called a mold control company and said we were going to leave the A/C on to keep the humidity down to prevent mold growth (we have a new A/C, very efficient, was going to keep it on the lowest setting just to dry the air a bit, so the energy usage would not have been a concern). They said not to do that. They're the "experts" so we followed their advice.



When we returned, the apartment had bloomed (literally bloomed) with mold.



Our landlord now is saying that this is because we use the A/C a lot (we don't), and need to open the unit windows more, and buy a dehumidifier. If we actually did use the A/C a lot, wouldn't the cooling and drying of the air have prevented the mold growth more than opening the unit?



We live next to a rainforest, so I would've thought that opening the unit would invite spores and damp air in rather than prevent mold?



Thanks in advance for any help






air-conditioning mold humidity




air-conditioning mold humidity






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited yesterday









isherwood

45.1k453115




45.1k453115










asked yesterday









ChristopherJChristopherJ

17816




17816




migrated from mechanics.stackexchange.com yesterday


This question came from our site for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles.






migrated from mechanics.stackexchange.com yesterday


This question came from our site for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles.










  • 3




    Odd that both parties would give you that flawed advice. I'm guessing that you don't pay utilities separately from your rent, giving the owner motivation to discourage AC use.
    – isherwood
    yesterday






  • 3




    There's one circumstance where I could see it being an issue -- if you run the AC aggressively during the day and cool down the house to, say 65 degrees, and then at night you open the windows and let warm moist 85 degree air in, it could cause condensation on walls and other surfaces.
    – Johnny
    yesterday








  • 5




    "and buy a dehumidifier" A/C is a dehumidifier.
    – Acccumulation
    yesterday






  • 2




    The lease contract places onus for repairs above $150 on the landlord - the mold outbreak occurred after slow repair of the waterlogged roof, so the landlord is incentivised to blame us for the mold. The A/Cs are about a month old, so unlikely they are the source of the mould
    – ChristopherJ
    17 hours ago






  • 2




    @JimmyJames Well, those in e.g. office buildings and hotels almost always have but a lot of newer systems for home use have a fresh air intake as well. It allows you to filter out pollen and pollution from the outside air for example. You can also pre-cool the intake air by routing it through the ground to increase efficiency.
    – Christian
    11 hours ago














  • 3




    Odd that both parties would give you that flawed advice. I'm guessing that you don't pay utilities separately from your rent, giving the owner motivation to discourage AC use.
    – isherwood
    yesterday






  • 3




    There's one circumstance where I could see it being an issue -- if you run the AC aggressively during the day and cool down the house to, say 65 degrees, and then at night you open the windows and let warm moist 85 degree air in, it could cause condensation on walls and other surfaces.
    – Johnny
    yesterday








  • 5




    "and buy a dehumidifier" A/C is a dehumidifier.
    – Acccumulation
    yesterday






  • 2




    The lease contract places onus for repairs above $150 on the landlord - the mold outbreak occurred after slow repair of the waterlogged roof, so the landlord is incentivised to blame us for the mold. The A/Cs are about a month old, so unlikely they are the source of the mould
    – ChristopherJ
    17 hours ago






  • 2




    @JimmyJames Well, those in e.g. office buildings and hotels almost always have but a lot of newer systems for home use have a fresh air intake as well. It allows you to filter out pollen and pollution from the outside air for example. You can also pre-cool the intake air by routing it through the ground to increase efficiency.
    – Christian
    11 hours ago








3




3




Odd that both parties would give you that flawed advice. I'm guessing that you don't pay utilities separately from your rent, giving the owner motivation to discourage AC use.
– isherwood
yesterday




Odd that both parties would give you that flawed advice. I'm guessing that you don't pay utilities separately from your rent, giving the owner motivation to discourage AC use.
– isherwood
yesterday




3




3




There's one circumstance where I could see it being an issue -- if you run the AC aggressively during the day and cool down the house to, say 65 degrees, and then at night you open the windows and let warm moist 85 degree air in, it could cause condensation on walls and other surfaces.
– Johnny
yesterday






There's one circumstance where I could see it being an issue -- if you run the AC aggressively during the day and cool down the house to, say 65 degrees, and then at night you open the windows and let warm moist 85 degree air in, it could cause condensation on walls and other surfaces.
– Johnny
yesterday






5




5




"and buy a dehumidifier" A/C is a dehumidifier.
– Acccumulation
yesterday




"and buy a dehumidifier" A/C is a dehumidifier.
– Acccumulation
yesterday




2




2




The lease contract places onus for repairs above $150 on the landlord - the mold outbreak occurred after slow repair of the waterlogged roof, so the landlord is incentivised to blame us for the mold. The A/Cs are about a month old, so unlikely they are the source of the mould
– ChristopherJ
17 hours ago




The lease contract places onus for repairs above $150 on the landlord - the mold outbreak occurred after slow repair of the waterlogged roof, so the landlord is incentivised to blame us for the mold. The A/Cs are about a month old, so unlikely they are the source of the mould
– ChristopherJ
17 hours ago




2




2




@JimmyJames Well, those in e.g. office buildings and hotels almost always have but a lot of newer systems for home use have a fresh air intake as well. It allows you to filter out pollen and pollution from the outside air for example. You can also pre-cool the intake air by routing it through the ground to increase efficiency.
– Christian
11 hours ago




@JimmyJames Well, those in e.g. office buildings and hotels almost always have but a lot of newer systems for home use have a fresh air intake as well. It allows you to filter out pollen and pollution from the outside air for example. You can also pre-cool the intake air by routing it through the ground to increase efficiency.
– Christian
11 hours ago










4 Answers
4






active

oldest

votes


















28














Yeah, that advice was super wrong. Moisture encourages mold growth.



After a water leak you need to go to extremes to dry the air to get wet things to evaporate into the air, which you then continue to dry. I would run dehumidifiers, or shoot, if your house has A/C, just run the A/C since that is a dehumidifier.



The only risk is if you excessively chill the air, because cooler air has less capacity to hold moisture. This drives the British crazy, their masonry buildings often have utility spaces with "the damp" which are 40-50F (5-10C) and freon dehumidifiers just don't work well at those temperatures. They are forced to heat the space just so the dehumidifier will work effectively. I've witnessed it myself, a dehumidifer that fills in 8 hours at 75F takes a week to fill at 45F. The goal is measured in gallons, and time is a factor, so that is a total lose. And mind you, dehumidifiers do heat the space since all the energy they use winds up in the room as heat. Air conditioners remove the heat.



So you need to also heat the house, which fortunately is something solar load (i.e. The sun hitting your roof) does automatically. All you need to do is have a system whereby the air conditioner doesn't cool the house more than it's being heated by the sun... Some sort of, gosh, I don't know, thermostat :)



Oh yeah, you have one of those. Set it aggressively enough to run a lot, but not so aggressively that you create the British problem. Something like 60-ish (16C), let it go nuts.






share|improve this answer























  • Yeah, i was sure that ACs dehumidify and opening up the windows in the tropics would bring in moisture, was starting to question myself after hearing it from two different sources
    – ChristopherJ
    17 hours ago










  • I don't think this is right. If you want to dry out your house, you need to have the AC running a lot. The reduced capacity of the air is inconsequential as the condenser will continually remove moisture and keep the ait below saturation.
    – JimmyJames
    14 hours ago










  • @JimmyJames You'll continually reduce the temperature, reducing evaporation. Cycling on and off will give the temperature to stabilise (obviously, to stay at the thermostat temp) and moisture to evaporate, before AC kicks in again to circulate and dehumidify what's airborne.
    – Dan
    13 hours ago










  • @Dan What you are missing is that the condenser is always colder than the air. It's like soaking up water with a damp sponge. A damp sponge can't hold as much water as a dry sponge but you can continually saturate it and wring it out in order to clean up more water than it can hold in total.
    – JimmyJames
    13 hours ago










  • @JimmyJames Yes, but that assumes it always has humid air passing over it. Constantly decreasing temperature will produce diminishing returns. It'll work, yes, but you're probably wasting energy for the same outcome.
    – Dan
    13 hours ago



















15














You are being sold.



The evaporator coil in the AC condenses water vapor in the air. It does this by blowing the warm air from your home over the cool evaporator coil. The cool coil pulls the moisture from the indoor air, removing it and draining it from your home via the condensate array. This happens with every air conditioning cycle. If the AC unit can't keep up with the humidity, the air will feel clammy and cool when it should feel dry and cool.



Get a humidity measuring tool so you always know what it is at (generally around $10 US). I don't know how bad the mold is but if it only on the surface, run the AC and in the meantime put on a respirator and use a bleach mix to remove/kill it.






share|improve this answer



















  • 4




    I use 3% hydrogen peroxide and water it kills the mold and you don't have the bleach smell. I do agree running the AC will reduce the humidity all the condensate coming from the evaporator coil is proof of this the only difference in a dehumidifier and AC is the AC dumps the heat outside where a dehumidifier dumps the heat in the same room so there is no cooling but they work the same.
    – Ed Beal
    yesterday



















10














It is possible for A/C to cause mold issues but it depends on a few factors. The problem is this: when choosing a A/C unit for a home, often people (even 'professionals') will assume that bigger is better. The installer plugs in the numbers to the manufacturers model and comes up with a recommended unit size, then bumps it up to a larger one.



The problem with this is that the larger unit will cool the home too quickly. It comes on, cools the air down and then shuts off. But because it only ran for a short time, the condenser did not have a chance to remove much moisture. Now you have cool, damp air in the home which results in moisture condensing in the walls. It may be the case that the mold control company has been called into to deal with such issues and that led to them giving that advice.



In order to dry the house out you need to have the A/C running continuously. Setting it on low (higher temperature) may lead to the A/C cutting on and off and if you have an over-sized unit and/or it isn't especially warm outside, it could make things worse. Setting the A/C to the lowest (warmest) setting that still keeps it on continuously is what you should do if you want to get your house bone dry.



Here are some references that discuss and help explain the issues caused by oversized units:




  • https://www.cooltoday.com/blog/3-problems-caused-by-an-oversized-air-conditioner

  • https://aristair.com/blog/hvac-humidity-control-5-reasons-your-ac-is-ineffective/

  • https://airexpertsnj.com/knowledge/entry/air-conditioner-not-dehumidifying-well-a-new-jersey-tech-explains-why

  • https://energyair.com/signs-ac-system-large/

  • https://trustcompleteair.com/signs-your-air-conditioner-is-too-big-oversized/

  • https://www.greenbuildingadvisor.com/article/coping-with-a-wrong-sized-ac-system






share|improve this answer























  • The US codes limit 'bumping' condensors to one size larger, for several reasons including this one. Others are energy efficiency and power plant load smoothing (toggling the system on and off too frequently) and carbon emissions (less volatile condensate out in the world).
    – brichins
    7 hours ago










  • This. If your AC unit is larger capacity than roughly 1-1.5 ton per thousand square feet, your home will stay humid. If that's the case you should try to make the fools who pressured you to get an inappropriately-sized system (to make more money off it) replace it with a suitably-sized one.
    – R..
    1 hour ago



















0














It can, but not for the reasons you think



Mold needs two key components to go wild like that




  1. Moisture

  2. A cool atmosphere


Your A/C can encourage mold growth by not running. If you leave your HVAC unit on cool and the surrounding air gets cool (i.e. a winter cold front blows through), the moisture in your house will condense and feed the mold. Then, when it warms up, the A/C starts up again, but now it's blowing the spores around. The humidity drop will help deter more growth, but what's there has to be dealt with to make the space habitable again.




We live next to a rainforest, so I would've thought that opening the unit would invite spores and damp air in rather than prevent mold?




The mold spores are already inside, A/C or not. Don't think of it as "letting more in". The issue with an open window next to a rain forest is humidity.






share|improve this answer





















  • Why would the air being cold outside cause moisture to condense inside?
    – JimmyJames
    14 hours ago










  • @JimmyJames This happened to my mother's house a few years ago. We moved her out but she still had some things inside. We left the A/C on. We then had a serious cold snap but no heater to keep the temperature level. We then discovered the mold had taken over when all that moisture condensed on the furniture.
    – Machavity
    13 hours ago










  • Sside from having an over-sized unit (see my answer) and assuming the water from the condenser is removed from the house (e.g. sump pump) and doesn't just dump in on the floor or something running the A/C is going to reduce the moisture in the home, not increase it.
    – JimmyJames
    13 hours ago










  • That's my point, tho. The HVAC will NOT run if it's set to cool and the house is already cool
    – Machavity
    13 hours ago






  • 2




    Running -> less moisture , Not-running -> no effect. Not seeing where the A/C increases moisture.
    – JimmyJames
    13 hours ago











Your Answer








StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "73"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fdiy.stackexchange.com%2fquestions%2f154304%2fdoes-a-c-encourage-mold-growth%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























4 Answers
4






active

oldest

votes








4 Answers
4






active

oldest

votes









active

oldest

votes






active

oldest

votes









28














Yeah, that advice was super wrong. Moisture encourages mold growth.



After a water leak you need to go to extremes to dry the air to get wet things to evaporate into the air, which you then continue to dry. I would run dehumidifiers, or shoot, if your house has A/C, just run the A/C since that is a dehumidifier.



The only risk is if you excessively chill the air, because cooler air has less capacity to hold moisture. This drives the British crazy, their masonry buildings often have utility spaces with "the damp" which are 40-50F (5-10C) and freon dehumidifiers just don't work well at those temperatures. They are forced to heat the space just so the dehumidifier will work effectively. I've witnessed it myself, a dehumidifer that fills in 8 hours at 75F takes a week to fill at 45F. The goal is measured in gallons, and time is a factor, so that is a total lose. And mind you, dehumidifiers do heat the space since all the energy they use winds up in the room as heat. Air conditioners remove the heat.



So you need to also heat the house, which fortunately is something solar load (i.e. The sun hitting your roof) does automatically. All you need to do is have a system whereby the air conditioner doesn't cool the house more than it's being heated by the sun... Some sort of, gosh, I don't know, thermostat :)



Oh yeah, you have one of those. Set it aggressively enough to run a lot, but not so aggressively that you create the British problem. Something like 60-ish (16C), let it go nuts.






share|improve this answer























  • Yeah, i was sure that ACs dehumidify and opening up the windows in the tropics would bring in moisture, was starting to question myself after hearing it from two different sources
    – ChristopherJ
    17 hours ago










  • I don't think this is right. If you want to dry out your house, you need to have the AC running a lot. The reduced capacity of the air is inconsequential as the condenser will continually remove moisture and keep the ait below saturation.
    – JimmyJames
    14 hours ago










  • @JimmyJames You'll continually reduce the temperature, reducing evaporation. Cycling on and off will give the temperature to stabilise (obviously, to stay at the thermostat temp) and moisture to evaporate, before AC kicks in again to circulate and dehumidify what's airborne.
    – Dan
    13 hours ago










  • @Dan What you are missing is that the condenser is always colder than the air. It's like soaking up water with a damp sponge. A damp sponge can't hold as much water as a dry sponge but you can continually saturate it and wring it out in order to clean up more water than it can hold in total.
    – JimmyJames
    13 hours ago










  • @JimmyJames Yes, but that assumes it always has humid air passing over it. Constantly decreasing temperature will produce diminishing returns. It'll work, yes, but you're probably wasting energy for the same outcome.
    – Dan
    13 hours ago
















28














Yeah, that advice was super wrong. Moisture encourages mold growth.



After a water leak you need to go to extremes to dry the air to get wet things to evaporate into the air, which you then continue to dry. I would run dehumidifiers, or shoot, if your house has A/C, just run the A/C since that is a dehumidifier.



The only risk is if you excessively chill the air, because cooler air has less capacity to hold moisture. This drives the British crazy, their masonry buildings often have utility spaces with "the damp" which are 40-50F (5-10C) and freon dehumidifiers just don't work well at those temperatures. They are forced to heat the space just so the dehumidifier will work effectively. I've witnessed it myself, a dehumidifer that fills in 8 hours at 75F takes a week to fill at 45F. The goal is measured in gallons, and time is a factor, so that is a total lose. And mind you, dehumidifiers do heat the space since all the energy they use winds up in the room as heat. Air conditioners remove the heat.



So you need to also heat the house, which fortunately is something solar load (i.e. The sun hitting your roof) does automatically. All you need to do is have a system whereby the air conditioner doesn't cool the house more than it's being heated by the sun... Some sort of, gosh, I don't know, thermostat :)



Oh yeah, you have one of those. Set it aggressively enough to run a lot, but not so aggressively that you create the British problem. Something like 60-ish (16C), let it go nuts.






share|improve this answer























  • Yeah, i was sure that ACs dehumidify and opening up the windows in the tropics would bring in moisture, was starting to question myself after hearing it from two different sources
    – ChristopherJ
    17 hours ago










  • I don't think this is right. If you want to dry out your house, you need to have the AC running a lot. The reduced capacity of the air is inconsequential as the condenser will continually remove moisture and keep the ait below saturation.
    – JimmyJames
    14 hours ago










  • @JimmyJames You'll continually reduce the temperature, reducing evaporation. Cycling on and off will give the temperature to stabilise (obviously, to stay at the thermostat temp) and moisture to evaporate, before AC kicks in again to circulate and dehumidify what's airborne.
    – Dan
    13 hours ago










  • @Dan What you are missing is that the condenser is always colder than the air. It's like soaking up water with a damp sponge. A damp sponge can't hold as much water as a dry sponge but you can continually saturate it and wring it out in order to clean up more water than it can hold in total.
    – JimmyJames
    13 hours ago










  • @JimmyJames Yes, but that assumes it always has humid air passing over it. Constantly decreasing temperature will produce diminishing returns. It'll work, yes, but you're probably wasting energy for the same outcome.
    – Dan
    13 hours ago














28












28








28






Yeah, that advice was super wrong. Moisture encourages mold growth.



After a water leak you need to go to extremes to dry the air to get wet things to evaporate into the air, which you then continue to dry. I would run dehumidifiers, or shoot, if your house has A/C, just run the A/C since that is a dehumidifier.



The only risk is if you excessively chill the air, because cooler air has less capacity to hold moisture. This drives the British crazy, their masonry buildings often have utility spaces with "the damp" which are 40-50F (5-10C) and freon dehumidifiers just don't work well at those temperatures. They are forced to heat the space just so the dehumidifier will work effectively. I've witnessed it myself, a dehumidifer that fills in 8 hours at 75F takes a week to fill at 45F. The goal is measured in gallons, and time is a factor, so that is a total lose. And mind you, dehumidifiers do heat the space since all the energy they use winds up in the room as heat. Air conditioners remove the heat.



So you need to also heat the house, which fortunately is something solar load (i.e. The sun hitting your roof) does automatically. All you need to do is have a system whereby the air conditioner doesn't cool the house more than it's being heated by the sun... Some sort of, gosh, I don't know, thermostat :)



Oh yeah, you have one of those. Set it aggressively enough to run a lot, but not so aggressively that you create the British problem. Something like 60-ish (16C), let it go nuts.






share|improve this answer














Yeah, that advice was super wrong. Moisture encourages mold growth.



After a water leak you need to go to extremes to dry the air to get wet things to evaporate into the air, which you then continue to dry. I would run dehumidifiers, or shoot, if your house has A/C, just run the A/C since that is a dehumidifier.



The only risk is if you excessively chill the air, because cooler air has less capacity to hold moisture. This drives the British crazy, their masonry buildings often have utility spaces with "the damp" which are 40-50F (5-10C) and freon dehumidifiers just don't work well at those temperatures. They are forced to heat the space just so the dehumidifier will work effectively. I've witnessed it myself, a dehumidifer that fills in 8 hours at 75F takes a week to fill at 45F. The goal is measured in gallons, and time is a factor, so that is a total lose. And mind you, dehumidifiers do heat the space since all the energy they use winds up in the room as heat. Air conditioners remove the heat.



So you need to also heat the house, which fortunately is something solar load (i.e. The sun hitting your roof) does automatically. All you need to do is have a system whereby the air conditioner doesn't cool the house more than it's being heated by the sun... Some sort of, gosh, I don't know, thermostat :)



Oh yeah, you have one of those. Set it aggressively enough to run a lot, but not so aggressively that you create the British problem. Something like 60-ish (16C), let it go nuts.







share|improve this answer














share|improve this answer



share|improve this answer








edited 12 hours ago

























answered yesterday









HarperHarper

66.5k344134




66.5k344134












  • Yeah, i was sure that ACs dehumidify and opening up the windows in the tropics would bring in moisture, was starting to question myself after hearing it from two different sources
    – ChristopherJ
    17 hours ago










  • I don't think this is right. If you want to dry out your house, you need to have the AC running a lot. The reduced capacity of the air is inconsequential as the condenser will continually remove moisture and keep the ait below saturation.
    – JimmyJames
    14 hours ago










  • @JimmyJames You'll continually reduce the temperature, reducing evaporation. Cycling on and off will give the temperature to stabilise (obviously, to stay at the thermostat temp) and moisture to evaporate, before AC kicks in again to circulate and dehumidify what's airborne.
    – Dan
    13 hours ago










  • @Dan What you are missing is that the condenser is always colder than the air. It's like soaking up water with a damp sponge. A damp sponge can't hold as much water as a dry sponge but you can continually saturate it and wring it out in order to clean up more water than it can hold in total.
    – JimmyJames
    13 hours ago










  • @JimmyJames Yes, but that assumes it always has humid air passing over it. Constantly decreasing temperature will produce diminishing returns. It'll work, yes, but you're probably wasting energy for the same outcome.
    – Dan
    13 hours ago


















  • Yeah, i was sure that ACs dehumidify and opening up the windows in the tropics would bring in moisture, was starting to question myself after hearing it from two different sources
    – ChristopherJ
    17 hours ago










  • I don't think this is right. If you want to dry out your house, you need to have the AC running a lot. The reduced capacity of the air is inconsequential as the condenser will continually remove moisture and keep the ait below saturation.
    – JimmyJames
    14 hours ago










  • @JimmyJames You'll continually reduce the temperature, reducing evaporation. Cycling on and off will give the temperature to stabilise (obviously, to stay at the thermostat temp) and moisture to evaporate, before AC kicks in again to circulate and dehumidify what's airborne.
    – Dan
    13 hours ago










  • @Dan What you are missing is that the condenser is always colder than the air. It's like soaking up water with a damp sponge. A damp sponge can't hold as much water as a dry sponge but you can continually saturate it and wring it out in order to clean up more water than it can hold in total.
    – JimmyJames
    13 hours ago










  • @JimmyJames Yes, but that assumes it always has humid air passing over it. Constantly decreasing temperature will produce diminishing returns. It'll work, yes, but you're probably wasting energy for the same outcome.
    – Dan
    13 hours ago
















Yeah, i was sure that ACs dehumidify and opening up the windows in the tropics would bring in moisture, was starting to question myself after hearing it from two different sources
– ChristopherJ
17 hours ago




Yeah, i was sure that ACs dehumidify and opening up the windows in the tropics would bring in moisture, was starting to question myself after hearing it from two different sources
– ChristopherJ
17 hours ago












I don't think this is right. If you want to dry out your house, you need to have the AC running a lot. The reduced capacity of the air is inconsequential as the condenser will continually remove moisture and keep the ait below saturation.
– JimmyJames
14 hours ago




I don't think this is right. If you want to dry out your house, you need to have the AC running a lot. The reduced capacity of the air is inconsequential as the condenser will continually remove moisture and keep the ait below saturation.
– JimmyJames
14 hours ago












@JimmyJames You'll continually reduce the temperature, reducing evaporation. Cycling on and off will give the temperature to stabilise (obviously, to stay at the thermostat temp) and moisture to evaporate, before AC kicks in again to circulate and dehumidify what's airborne.
– Dan
13 hours ago




@JimmyJames You'll continually reduce the temperature, reducing evaporation. Cycling on and off will give the temperature to stabilise (obviously, to stay at the thermostat temp) and moisture to evaporate, before AC kicks in again to circulate and dehumidify what's airborne.
– Dan
13 hours ago












@Dan What you are missing is that the condenser is always colder than the air. It's like soaking up water with a damp sponge. A damp sponge can't hold as much water as a dry sponge but you can continually saturate it and wring it out in order to clean up more water than it can hold in total.
– JimmyJames
13 hours ago




@Dan What you are missing is that the condenser is always colder than the air. It's like soaking up water with a damp sponge. A damp sponge can't hold as much water as a dry sponge but you can continually saturate it and wring it out in order to clean up more water than it can hold in total.
– JimmyJames
13 hours ago












@JimmyJames Yes, but that assumes it always has humid air passing over it. Constantly decreasing temperature will produce diminishing returns. It'll work, yes, but you're probably wasting energy for the same outcome.
– Dan
13 hours ago




@JimmyJames Yes, but that assumes it always has humid air passing over it. Constantly decreasing temperature will produce diminishing returns. It'll work, yes, but you're probably wasting energy for the same outcome.
– Dan
13 hours ago













15














You are being sold.



The evaporator coil in the AC condenses water vapor in the air. It does this by blowing the warm air from your home over the cool evaporator coil. The cool coil pulls the moisture from the indoor air, removing it and draining it from your home via the condensate array. This happens with every air conditioning cycle. If the AC unit can't keep up with the humidity, the air will feel clammy and cool when it should feel dry and cool.



Get a humidity measuring tool so you always know what it is at (generally around $10 US). I don't know how bad the mold is but if it only on the surface, run the AC and in the meantime put on a respirator and use a bleach mix to remove/kill it.






share|improve this answer



















  • 4




    I use 3% hydrogen peroxide and water it kills the mold and you don't have the bleach smell. I do agree running the AC will reduce the humidity all the condensate coming from the evaporator coil is proof of this the only difference in a dehumidifier and AC is the AC dumps the heat outside where a dehumidifier dumps the heat in the same room so there is no cooling but they work the same.
    – Ed Beal
    yesterday
















15














You are being sold.



The evaporator coil in the AC condenses water vapor in the air. It does this by blowing the warm air from your home over the cool evaporator coil. The cool coil pulls the moisture from the indoor air, removing it and draining it from your home via the condensate array. This happens with every air conditioning cycle. If the AC unit can't keep up with the humidity, the air will feel clammy and cool when it should feel dry and cool.



Get a humidity measuring tool so you always know what it is at (generally around $10 US). I don't know how bad the mold is but if it only on the surface, run the AC and in the meantime put on a respirator and use a bleach mix to remove/kill it.






share|improve this answer



















  • 4




    I use 3% hydrogen peroxide and water it kills the mold and you don't have the bleach smell. I do agree running the AC will reduce the humidity all the condensate coming from the evaporator coil is proof of this the only difference in a dehumidifier and AC is the AC dumps the heat outside where a dehumidifier dumps the heat in the same room so there is no cooling but they work the same.
    – Ed Beal
    yesterday














15












15








15






You are being sold.



The evaporator coil in the AC condenses water vapor in the air. It does this by blowing the warm air from your home over the cool evaporator coil. The cool coil pulls the moisture from the indoor air, removing it and draining it from your home via the condensate array. This happens with every air conditioning cycle. If the AC unit can't keep up with the humidity, the air will feel clammy and cool when it should feel dry and cool.



Get a humidity measuring tool so you always know what it is at (generally around $10 US). I don't know how bad the mold is but if it only on the surface, run the AC and in the meantime put on a respirator and use a bleach mix to remove/kill it.






share|improve this answer














You are being sold.



The evaporator coil in the AC condenses water vapor in the air. It does this by blowing the warm air from your home over the cool evaporator coil. The cool coil pulls the moisture from the indoor air, removing it and draining it from your home via the condensate array. This happens with every air conditioning cycle. If the AC unit can't keep up with the humidity, the air will feel clammy and cool when it should feel dry and cool.



Get a humidity measuring tool so you always know what it is at (generally around $10 US). I don't know how bad the mold is but if it only on the surface, run the AC and in the meantime put on a respirator and use a bleach mix to remove/kill it.







share|improve this answer














share|improve this answer



share|improve this answer








edited yesterday









isherwood

45.1k453115




45.1k453115










answered yesterday









Micah MontoyaMicah Montoya

37116




37116








  • 4




    I use 3% hydrogen peroxide and water it kills the mold and you don't have the bleach smell. I do agree running the AC will reduce the humidity all the condensate coming from the evaporator coil is proof of this the only difference in a dehumidifier and AC is the AC dumps the heat outside where a dehumidifier dumps the heat in the same room so there is no cooling but they work the same.
    – Ed Beal
    yesterday














  • 4




    I use 3% hydrogen peroxide and water it kills the mold and you don't have the bleach smell. I do agree running the AC will reduce the humidity all the condensate coming from the evaporator coil is proof of this the only difference in a dehumidifier and AC is the AC dumps the heat outside where a dehumidifier dumps the heat in the same room so there is no cooling but they work the same.
    – Ed Beal
    yesterday








4




4




I use 3% hydrogen peroxide and water it kills the mold and you don't have the bleach smell. I do agree running the AC will reduce the humidity all the condensate coming from the evaporator coil is proof of this the only difference in a dehumidifier and AC is the AC dumps the heat outside where a dehumidifier dumps the heat in the same room so there is no cooling but they work the same.
– Ed Beal
yesterday




I use 3% hydrogen peroxide and water it kills the mold and you don't have the bleach smell. I do agree running the AC will reduce the humidity all the condensate coming from the evaporator coil is proof of this the only difference in a dehumidifier and AC is the AC dumps the heat outside where a dehumidifier dumps the heat in the same room so there is no cooling but they work the same.
– Ed Beal
yesterday











10














It is possible for A/C to cause mold issues but it depends on a few factors. The problem is this: when choosing a A/C unit for a home, often people (even 'professionals') will assume that bigger is better. The installer plugs in the numbers to the manufacturers model and comes up with a recommended unit size, then bumps it up to a larger one.



The problem with this is that the larger unit will cool the home too quickly. It comes on, cools the air down and then shuts off. But because it only ran for a short time, the condenser did not have a chance to remove much moisture. Now you have cool, damp air in the home which results in moisture condensing in the walls. It may be the case that the mold control company has been called into to deal with such issues and that led to them giving that advice.



In order to dry the house out you need to have the A/C running continuously. Setting it on low (higher temperature) may lead to the A/C cutting on and off and if you have an over-sized unit and/or it isn't especially warm outside, it could make things worse. Setting the A/C to the lowest (warmest) setting that still keeps it on continuously is what you should do if you want to get your house bone dry.



Here are some references that discuss and help explain the issues caused by oversized units:




  • https://www.cooltoday.com/blog/3-problems-caused-by-an-oversized-air-conditioner

  • https://aristair.com/blog/hvac-humidity-control-5-reasons-your-ac-is-ineffective/

  • https://airexpertsnj.com/knowledge/entry/air-conditioner-not-dehumidifying-well-a-new-jersey-tech-explains-why

  • https://energyair.com/signs-ac-system-large/

  • https://trustcompleteair.com/signs-your-air-conditioner-is-too-big-oversized/

  • https://www.greenbuildingadvisor.com/article/coping-with-a-wrong-sized-ac-system






share|improve this answer























  • The US codes limit 'bumping' condensors to one size larger, for several reasons including this one. Others are energy efficiency and power plant load smoothing (toggling the system on and off too frequently) and carbon emissions (less volatile condensate out in the world).
    – brichins
    7 hours ago










  • This. If your AC unit is larger capacity than roughly 1-1.5 ton per thousand square feet, your home will stay humid. If that's the case you should try to make the fools who pressured you to get an inappropriately-sized system (to make more money off it) replace it with a suitably-sized one.
    – R..
    1 hour ago
















10














It is possible for A/C to cause mold issues but it depends on a few factors. The problem is this: when choosing a A/C unit for a home, often people (even 'professionals') will assume that bigger is better. The installer plugs in the numbers to the manufacturers model and comes up with a recommended unit size, then bumps it up to a larger one.



The problem with this is that the larger unit will cool the home too quickly. It comes on, cools the air down and then shuts off. But because it only ran for a short time, the condenser did not have a chance to remove much moisture. Now you have cool, damp air in the home which results in moisture condensing in the walls. It may be the case that the mold control company has been called into to deal with such issues and that led to them giving that advice.



In order to dry the house out you need to have the A/C running continuously. Setting it on low (higher temperature) may lead to the A/C cutting on and off and if you have an over-sized unit and/or it isn't especially warm outside, it could make things worse. Setting the A/C to the lowest (warmest) setting that still keeps it on continuously is what you should do if you want to get your house bone dry.



Here are some references that discuss and help explain the issues caused by oversized units:




  • https://www.cooltoday.com/blog/3-problems-caused-by-an-oversized-air-conditioner

  • https://aristair.com/blog/hvac-humidity-control-5-reasons-your-ac-is-ineffective/

  • https://airexpertsnj.com/knowledge/entry/air-conditioner-not-dehumidifying-well-a-new-jersey-tech-explains-why

  • https://energyair.com/signs-ac-system-large/

  • https://trustcompleteair.com/signs-your-air-conditioner-is-too-big-oversized/

  • https://www.greenbuildingadvisor.com/article/coping-with-a-wrong-sized-ac-system






share|improve this answer























  • The US codes limit 'bumping' condensors to one size larger, for several reasons including this one. Others are energy efficiency and power plant load smoothing (toggling the system on and off too frequently) and carbon emissions (less volatile condensate out in the world).
    – brichins
    7 hours ago










  • This. If your AC unit is larger capacity than roughly 1-1.5 ton per thousand square feet, your home will stay humid. If that's the case you should try to make the fools who pressured you to get an inappropriately-sized system (to make more money off it) replace it with a suitably-sized one.
    – R..
    1 hour ago














10












10








10






It is possible for A/C to cause mold issues but it depends on a few factors. The problem is this: when choosing a A/C unit for a home, often people (even 'professionals') will assume that bigger is better. The installer plugs in the numbers to the manufacturers model and comes up with a recommended unit size, then bumps it up to a larger one.



The problem with this is that the larger unit will cool the home too quickly. It comes on, cools the air down and then shuts off. But because it only ran for a short time, the condenser did not have a chance to remove much moisture. Now you have cool, damp air in the home which results in moisture condensing in the walls. It may be the case that the mold control company has been called into to deal with such issues and that led to them giving that advice.



In order to dry the house out you need to have the A/C running continuously. Setting it on low (higher temperature) may lead to the A/C cutting on and off and if you have an over-sized unit and/or it isn't especially warm outside, it could make things worse. Setting the A/C to the lowest (warmest) setting that still keeps it on continuously is what you should do if you want to get your house bone dry.



Here are some references that discuss and help explain the issues caused by oversized units:




  • https://www.cooltoday.com/blog/3-problems-caused-by-an-oversized-air-conditioner

  • https://aristair.com/blog/hvac-humidity-control-5-reasons-your-ac-is-ineffective/

  • https://airexpertsnj.com/knowledge/entry/air-conditioner-not-dehumidifying-well-a-new-jersey-tech-explains-why

  • https://energyair.com/signs-ac-system-large/

  • https://trustcompleteair.com/signs-your-air-conditioner-is-too-big-oversized/

  • https://www.greenbuildingadvisor.com/article/coping-with-a-wrong-sized-ac-system






share|improve this answer














It is possible for A/C to cause mold issues but it depends on a few factors. The problem is this: when choosing a A/C unit for a home, often people (even 'professionals') will assume that bigger is better. The installer plugs in the numbers to the manufacturers model and comes up with a recommended unit size, then bumps it up to a larger one.



The problem with this is that the larger unit will cool the home too quickly. It comes on, cools the air down and then shuts off. But because it only ran for a short time, the condenser did not have a chance to remove much moisture. Now you have cool, damp air in the home which results in moisture condensing in the walls. It may be the case that the mold control company has been called into to deal with such issues and that led to them giving that advice.



In order to dry the house out you need to have the A/C running continuously. Setting it on low (higher temperature) may lead to the A/C cutting on and off and if you have an over-sized unit and/or it isn't especially warm outside, it could make things worse. Setting the A/C to the lowest (warmest) setting that still keeps it on continuously is what you should do if you want to get your house bone dry.



Here are some references that discuss and help explain the issues caused by oversized units:




  • https://www.cooltoday.com/blog/3-problems-caused-by-an-oversized-air-conditioner

  • https://aristair.com/blog/hvac-humidity-control-5-reasons-your-ac-is-ineffective/

  • https://airexpertsnj.com/knowledge/entry/air-conditioner-not-dehumidifying-well-a-new-jersey-tech-explains-why

  • https://energyair.com/signs-ac-system-large/

  • https://trustcompleteair.com/signs-your-air-conditioner-is-too-big-oversized/

  • https://www.greenbuildingadvisor.com/article/coping-with-a-wrong-sized-ac-system







share|improve this answer














share|improve this answer



share|improve this answer








edited 8 hours ago

























answered 14 hours ago









JimmyJamesJimmyJames

736616




736616












  • The US codes limit 'bumping' condensors to one size larger, for several reasons including this one. Others are energy efficiency and power plant load smoothing (toggling the system on and off too frequently) and carbon emissions (less volatile condensate out in the world).
    – brichins
    7 hours ago










  • This. If your AC unit is larger capacity than roughly 1-1.5 ton per thousand square feet, your home will stay humid. If that's the case you should try to make the fools who pressured you to get an inappropriately-sized system (to make more money off it) replace it with a suitably-sized one.
    – R..
    1 hour ago


















  • The US codes limit 'bumping' condensors to one size larger, for several reasons including this one. Others are energy efficiency and power plant load smoothing (toggling the system on and off too frequently) and carbon emissions (less volatile condensate out in the world).
    – brichins
    7 hours ago










  • This. If your AC unit is larger capacity than roughly 1-1.5 ton per thousand square feet, your home will stay humid. If that's the case you should try to make the fools who pressured you to get an inappropriately-sized system (to make more money off it) replace it with a suitably-sized one.
    – R..
    1 hour ago
















The US codes limit 'bumping' condensors to one size larger, for several reasons including this one. Others are energy efficiency and power plant load smoothing (toggling the system on and off too frequently) and carbon emissions (less volatile condensate out in the world).
– brichins
7 hours ago




The US codes limit 'bumping' condensors to one size larger, for several reasons including this one. Others are energy efficiency and power plant load smoothing (toggling the system on and off too frequently) and carbon emissions (less volatile condensate out in the world).
– brichins
7 hours ago












This. If your AC unit is larger capacity than roughly 1-1.5 ton per thousand square feet, your home will stay humid. If that's the case you should try to make the fools who pressured you to get an inappropriately-sized system (to make more money off it) replace it with a suitably-sized one.
– R..
1 hour ago




This. If your AC unit is larger capacity than roughly 1-1.5 ton per thousand square feet, your home will stay humid. If that's the case you should try to make the fools who pressured you to get an inappropriately-sized system (to make more money off it) replace it with a suitably-sized one.
– R..
1 hour ago











0














It can, but not for the reasons you think



Mold needs two key components to go wild like that




  1. Moisture

  2. A cool atmosphere


Your A/C can encourage mold growth by not running. If you leave your HVAC unit on cool and the surrounding air gets cool (i.e. a winter cold front blows through), the moisture in your house will condense and feed the mold. Then, when it warms up, the A/C starts up again, but now it's blowing the spores around. The humidity drop will help deter more growth, but what's there has to be dealt with to make the space habitable again.




We live next to a rainforest, so I would've thought that opening the unit would invite spores and damp air in rather than prevent mold?




The mold spores are already inside, A/C or not. Don't think of it as "letting more in". The issue with an open window next to a rain forest is humidity.






share|improve this answer





















  • Why would the air being cold outside cause moisture to condense inside?
    – JimmyJames
    14 hours ago










  • @JimmyJames This happened to my mother's house a few years ago. We moved her out but she still had some things inside. We left the A/C on. We then had a serious cold snap but no heater to keep the temperature level. We then discovered the mold had taken over when all that moisture condensed on the furniture.
    – Machavity
    13 hours ago










  • Sside from having an over-sized unit (see my answer) and assuming the water from the condenser is removed from the house (e.g. sump pump) and doesn't just dump in on the floor or something running the A/C is going to reduce the moisture in the home, not increase it.
    – JimmyJames
    13 hours ago










  • That's my point, tho. The HVAC will NOT run if it's set to cool and the house is already cool
    – Machavity
    13 hours ago






  • 2




    Running -> less moisture , Not-running -> no effect. Not seeing where the A/C increases moisture.
    – JimmyJames
    13 hours ago
















0














It can, but not for the reasons you think



Mold needs two key components to go wild like that




  1. Moisture

  2. A cool atmosphere


Your A/C can encourage mold growth by not running. If you leave your HVAC unit on cool and the surrounding air gets cool (i.e. a winter cold front blows through), the moisture in your house will condense and feed the mold. Then, when it warms up, the A/C starts up again, but now it's blowing the spores around. The humidity drop will help deter more growth, but what's there has to be dealt with to make the space habitable again.




We live next to a rainforest, so I would've thought that opening the unit would invite spores and damp air in rather than prevent mold?




The mold spores are already inside, A/C or not. Don't think of it as "letting more in". The issue with an open window next to a rain forest is humidity.






share|improve this answer





















  • Why would the air being cold outside cause moisture to condense inside?
    – JimmyJames
    14 hours ago










  • @JimmyJames This happened to my mother's house a few years ago. We moved her out but she still had some things inside. We left the A/C on. We then had a serious cold snap but no heater to keep the temperature level. We then discovered the mold had taken over when all that moisture condensed on the furniture.
    – Machavity
    13 hours ago










  • Sside from having an over-sized unit (see my answer) and assuming the water from the condenser is removed from the house (e.g. sump pump) and doesn't just dump in on the floor or something running the A/C is going to reduce the moisture in the home, not increase it.
    – JimmyJames
    13 hours ago










  • That's my point, tho. The HVAC will NOT run if it's set to cool and the house is already cool
    – Machavity
    13 hours ago






  • 2




    Running -> less moisture , Not-running -> no effect. Not seeing where the A/C increases moisture.
    – JimmyJames
    13 hours ago














0












0








0






It can, but not for the reasons you think



Mold needs two key components to go wild like that




  1. Moisture

  2. A cool atmosphere


Your A/C can encourage mold growth by not running. If you leave your HVAC unit on cool and the surrounding air gets cool (i.e. a winter cold front blows through), the moisture in your house will condense and feed the mold. Then, when it warms up, the A/C starts up again, but now it's blowing the spores around. The humidity drop will help deter more growth, but what's there has to be dealt with to make the space habitable again.




We live next to a rainforest, so I would've thought that opening the unit would invite spores and damp air in rather than prevent mold?




The mold spores are already inside, A/C or not. Don't think of it as "letting more in". The issue with an open window next to a rain forest is humidity.






share|improve this answer












It can, but not for the reasons you think



Mold needs two key components to go wild like that




  1. Moisture

  2. A cool atmosphere


Your A/C can encourage mold growth by not running. If you leave your HVAC unit on cool and the surrounding air gets cool (i.e. a winter cold front blows through), the moisture in your house will condense and feed the mold. Then, when it warms up, the A/C starts up again, but now it's blowing the spores around. The humidity drop will help deter more growth, but what's there has to be dealt with to make the space habitable again.




We live next to a rainforest, so I would've thought that opening the unit would invite spores and damp air in rather than prevent mold?




The mold spores are already inside, A/C or not. Don't think of it as "letting more in". The issue with an open window next to a rain forest is humidity.







share|improve this answer












share|improve this answer



share|improve this answer










answered 14 hours ago









MachavityMachavity

6,61511634




6,61511634












  • Why would the air being cold outside cause moisture to condense inside?
    – JimmyJames
    14 hours ago










  • @JimmyJames This happened to my mother's house a few years ago. We moved her out but she still had some things inside. We left the A/C on. We then had a serious cold snap but no heater to keep the temperature level. We then discovered the mold had taken over when all that moisture condensed on the furniture.
    – Machavity
    13 hours ago










  • Sside from having an over-sized unit (see my answer) and assuming the water from the condenser is removed from the house (e.g. sump pump) and doesn't just dump in on the floor or something running the A/C is going to reduce the moisture in the home, not increase it.
    – JimmyJames
    13 hours ago










  • That's my point, tho. The HVAC will NOT run if it's set to cool and the house is already cool
    – Machavity
    13 hours ago






  • 2




    Running -> less moisture , Not-running -> no effect. Not seeing where the A/C increases moisture.
    – JimmyJames
    13 hours ago


















  • Why would the air being cold outside cause moisture to condense inside?
    – JimmyJames
    14 hours ago










  • @JimmyJames This happened to my mother's house a few years ago. We moved her out but she still had some things inside. We left the A/C on. We then had a serious cold snap but no heater to keep the temperature level. We then discovered the mold had taken over when all that moisture condensed on the furniture.
    – Machavity
    13 hours ago










  • Sside from having an over-sized unit (see my answer) and assuming the water from the condenser is removed from the house (e.g. sump pump) and doesn't just dump in on the floor or something running the A/C is going to reduce the moisture in the home, not increase it.
    – JimmyJames
    13 hours ago










  • That's my point, tho. The HVAC will NOT run if it's set to cool and the house is already cool
    – Machavity
    13 hours ago






  • 2




    Running -> less moisture , Not-running -> no effect. Not seeing where the A/C increases moisture.
    – JimmyJames
    13 hours ago
















Why would the air being cold outside cause moisture to condense inside?
– JimmyJames
14 hours ago




Why would the air being cold outside cause moisture to condense inside?
– JimmyJames
14 hours ago












@JimmyJames This happened to my mother's house a few years ago. We moved her out but she still had some things inside. We left the A/C on. We then had a serious cold snap but no heater to keep the temperature level. We then discovered the mold had taken over when all that moisture condensed on the furniture.
– Machavity
13 hours ago




@JimmyJames This happened to my mother's house a few years ago. We moved her out but she still had some things inside. We left the A/C on. We then had a serious cold snap but no heater to keep the temperature level. We then discovered the mold had taken over when all that moisture condensed on the furniture.
– Machavity
13 hours ago












Sside from having an over-sized unit (see my answer) and assuming the water from the condenser is removed from the house (e.g. sump pump) and doesn't just dump in on the floor or something running the A/C is going to reduce the moisture in the home, not increase it.
– JimmyJames
13 hours ago




Sside from having an over-sized unit (see my answer) and assuming the water from the condenser is removed from the house (e.g. sump pump) and doesn't just dump in on the floor or something running the A/C is going to reduce the moisture in the home, not increase it.
– JimmyJames
13 hours ago












That's my point, tho. The HVAC will NOT run if it's set to cool and the house is already cool
– Machavity
13 hours ago




That's my point, tho. The HVAC will NOT run if it's set to cool and the house is already cool
– Machavity
13 hours ago




2




2




Running -> less moisture , Not-running -> no effect. Not seeing where the A/C increases moisture.
– JimmyJames
13 hours ago




Running -> less moisture , Not-running -> no effect. Not seeing where the A/C increases moisture.
– JimmyJames
13 hours ago


















draft saved

draft discarded




















































Thanks for contributing an answer to Home Improvement Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid …



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


To learn more, see our tips on writing great answers.





Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


Please pay close attention to the following guidance:


  • Please be sure to answer the question. Provide details and share your research!

But avoid …



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fdiy.stackexchange.com%2fquestions%2f154304%2fdoes-a-c-encourage-mold-growth%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







-

Popular posts from this blog

1300-talet

Image
Den här artikeln handlar om hundraårsperioden 1300–1399. För decenniet 1300–1309, se 1300-talet (decennium). .mw-parser-output .infobox{border:1px solid #aaa;background-color:#f9f9f9;color:black;margin:.5em 0 .5em 1em;padding:.2em;float:right;clear:right;width:22em;text-align:left;font-size:88%;line-height:1.6em}.mw-parser-output .infobox td,.mw-parser-output .infobox th{vertical-align:top;padding:0 .2em}.mw-parser-output .infobox caption{font-size:larger}.mw-parser-output .infobox.bordered{border-collapse:collapse}.mw-parser-output .infobox.bordered td,.mw-parser-output .infobox.bordered th{border:1px solid #aaa}.mw-parser-output .infobox.bordered .borderless td,.mw-parser-output .infobox.bordered .borderless th{border:0}.mw-parser-output .infobox-showbutton .mw-collapsible-text{color:inherit}.mw-parser-output .infobox.bordered .mergedtoprow td,.mw-parser-output .infobox.bordered .mergedtoprow th{border:0;border-top:1px solid #aaa;border-right:1px solid #aaa}.mw-parser-output ...
Read more

1300-talet

Image
Den här artikeln handlar om hundraårsperioden 1300–1399. För decenniet 1300–1309, se 1300-talet (decennium). .mw-parser-output .infobox{border:1px solid #aaa;background-color:#f9f9f9;color:black;margin:.5em 0 .5em 1em;padding:.2em;float:right;clear:right;width:22em;text-align:left;font-size:88%;line-height:1.6em}.mw-parser-output .infobox td,.mw-parser-output .infobox th{vertical-align:top;padding:0 .2em}.mw-parser-output .infobox caption{font-size:larger}.mw-parser-output .infobox.bordered{border-collapse:collapse}.mw-parser-output .infobox.bordered td,.mw-parser-output .infobox.bordered th{border:1px solid #aaa}.mw-parser-output .infobox.bordered .borderless td,.mw-parser-output .infobox.bordered .borderless th{border:0}.mw-parser-output .infobox-showbutton .mw-collapsible-text{color:inherit}.mw-parser-output .infobox.bordered .mergedtoprow td,.mw-parser-output .infobox.bordered .mergedtoprow th{border:0;border-top:1px solid #aaa;border-right:1px solid #aaa}.mw-parser-output ...
Read more

Display a custom attribute below product name in the front-end Magento 1.9.3.8

Image
0 I need to display a custom attribute bellow the product name and I don't know how can I call this attribute. I am editing the file /app/design/frontend/templatemela/MAG100219_1/template/catalog/product/view.phtml But how can I call this attribute in php? I tried calling a string echo with the name I put in the attribute, but it didn't work. Code is as below: <div class="page-title product-title"> <h1><?php echo $_helper->productAttribute($_product, $_product->getName(), 'name') ?></h1> </div> <div class="codigoinmetro"> <h2><?php echo $_helper->productAttribute($_product, $_product->getName(), 'registroinmetro') ?></h2> </div> php attrib...
Read more