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Indoor Humidity Issues


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I recently moved into a large house and have been having allergy problems. After some testing, it turns out I am allergic to fungus and mold spores. Thai doctor recommended using a dehumidifier if the humidity in the house is above 50%.

 

All of the ACs in the house are new (new house) and have a DRY function, but it seems they only bring the humidity of any given room to maybe 65%-70 briefly... I never get anywhere near the below 50% that I'm supposed to reach.

 

Since the AC's couldn't cope I bought two 2L tank humidifiers and started running them nonstop in the most humid rooms (sometimes reaching over 80% humidity) and have been emptying tons of water that has been sucked out of the air. Liters and liters of moisture...

 

The humidity is dropping in those rooms, but I'm still struggling to keep the humidity below 60... still no where near below 50. This is baffling to me.

 

 

 

With this data in mind, should I assume that there is an undetected water leak or compromise somewhere? If the AC isn't capable of drying the air below 50, even with a DRY function and two humidifiers on the same floor isn't getting me there, it seems that there is a serious amount of moisture leaking in from somewhere. Or perhaps a ventilation problem that is causing the ACs to send in moisture rather than send it out.

 

There were some water leaks in the house that seemed not so serious that have been fixed... When I had an technician try to fix condensation on the top floor AC, he offered no solution other than keep the bedroom door shut when using the AC... I didn't have time to argue, even though that seemed like *not* a solution to condensation, caused by too much humidity or faulty ac.

 

 

Even with the doctor telling me to get below 50%, I am starting to second guess myself and wonder if my house humidity actually can't be brought down to that level. Even though outdoor humidity is 70+ on many days, seems unlikely that indoor humidity would be this difficult to control without a compromise somewhere... no matter what the outdoor level is.

 

Are you other other people in BKK experiencing uncontrollable indoor humidity or do I have a water issue somewhere?

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You could still have a slow leak if the pipes are buried in the floor or walls,I had one or a few still don't know exactly where for years, in the end I just re plumbed the whole lot but did not bury

Farang51, you are totally wrong.

My suggestion, which will not bring the humidity down but keeps away the mold/fungus is: open all the windows to create airflow. If you really need the aircon in one room, shut the door and windo

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My suggestion, which will not bring the humidity down but keeps away the mold/fungus is:

open all the windows to create airflow. If you really need the aircon in one room, shut the door and windows when in use and open if not. I have a friend who has a similar problem in the bungalows of his resort. Bathroom is also a factor.

Otherwise you would have to shut everything and run aircon permanently

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1 hour ago, pikao said:

My suggestion, which will not bring the humidity down but keeps away the mold/fungus is:

open all the windows to create airflow. If you really need the aircon in one room, shut the door and windows when in use and open if not. I have a friend who has a similar problem in the bungalows of his resort. Bathroom is also a factor.

Otherwise you would have to shut everything and run aircon permanently

My previous attitude was to keep everything sealed off and run AC constantly with off days running fan only mode or opening windows to vent in fresh air.. This worked fine in most every condo that I lived in before.

 

Now I am thinking in this house I will have to open the windows on the top floor during daytime to help air vent things out and then close them up and run AC everywhere at night. The house is several floors, so fans alone cannot keep it cool... But I actually don't mind being hot. I don't even like the AC. But the humidity above 60 is unbearable sometimes... Even if you don't feel hot, you'll wake up sweating, and since I can't keep everything opened all the time, there's the mold fear when I have to close things back up too.

 

 

1 hour ago, johng said:

For the aircon to remove humidity you need to shut the windows and doors and seal the room up from the outside hot humid air  if you leave the door open then you will either be trying to  air condition the whole world or an infeasibly large volume that the aircon unit cannot cope with.

 

Do you mean shut the room off to all other rooms or to the outside (outdoors)? I definitely don't open any outside doors/windows when the AC is in use, but will often run the AC with that particular bedroom's door open to the rest of the house. I usually keep all bedroom doors open to the rest of the house to promote air circulation and not allow any one room to get stuffy. This house has many AC units. Yesterday, I turned all of them on at once (total of 8)... Dry mode a couple hours and then the coldest possible setting for a while... Yet the humidity hoovered around 65 all throughout the house.

 

To give you an example of how weird it is... The current outside humidity in BKK is 62 and the temperature is 32... Yet inside one room in my house, I am reading humidity of 63.... a little higher than outside, despite the AC being on and sending in cool air. With all doors and windows in that room shut, you would think that if the outside humidity is 62, an AC unit could easily bring the humidity below 50 within just a couple hours. I mean.. doesn't the AC evaporate the air and vent out the moisture in order to send in cool air. Something definitely seems wrong if the ACs alone cannot accomplish this task alone.

 

Electronic Dehumidifiers aren't even a popular thing in BKK, so I can't imagine this issue I'm having is something common here. Otherwise how is everyone else handling it? I can't imagine everyone else would leave their house above mold/fungus growth levels.

 

Also for context... Only one bathroom is is used for showers in this house, and I don't cook or boil water, or hang wet clothes or anything like that. There's no logical reason I can think of excess moisture getting inside other than a leak of some sort. That is of course, unless there is some weird thing in BKK I don't understand or something about concrete houses I don't understand. I'm definately no expert on Thai weather or humidity, and this is the first house in Thailand I've lived in.

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If you are using 'split' ACs then the 'dry' function utilizes the dewpoint phenomenon that collects moisture on cooled coils that drip into a collection tray and exit via a drain tube to the outside.

 

If you have allergies it's very important to have your ACs filters, coils, drip collection tray, and drain tube cleaned on a regular basis to avoid having them become petri dishes.

 

While you can also invest in room sterilization devices like UVClight, ozone generators, or dedicated room air purifiers to keep active airborne contaminates at bay, a simpler approach is the one pikao already suggested.

 

 

 

 

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28 minutes ago, dia1 said:

there is some weird thing in BKK I don't understand or something about concrete houses I don't understand

Maybe rising damp ?  they often build with no damp proof course or vapour barriers...

is the house  free standing or have shared walls with neighbours ?  maybe they have a leak.

 

31 minutes ago, dia1 said:

Do you mean shut the room off to all other rooms or to the outside (outdoors)?

Yes shut off the room from other rooms and from the outside...how cold does the room actually get  ?

never mind what the remote control setting says.

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5 hours ago, johng said:

Maybe rising damp ?  they often build with no damp proof course or vapour barriers...

is the house  free standing or have shared walls with neighbours ?  maybe they have a leak.

 

Yes shut off the room from other rooms and from the outside...how cold does the room actually get  ?

never mind what the remote control setting says.

It's a townhouse sharing walls on both sides. You might be right about the rising damp, but I suspect a leak from rain.

 

If I shut off any given room to other rooms and the outside, it depends on the room and time of day. The worst offending room on the top floor struggles to get to 25 degrees on a hot day, but once the sun goes down, it can get to around 20. I rarely if ever turn on the a/c there because the humidity will cause condensation to form on the ac's vent. Today, after running the dehumidifer in that room sealed off and getting it down to around 55 humidity temporarily, I removed the humidifier and turned the AC on to its lowest setting. It managed to get the room to 20 degrees after an hour or so by running alone, but the humidity jumped up to over 70. I think in that particular room there might actually a ventilation problem or problem with the AC coils, because it makes no sense how the humidity rose as the AC cooled the room.

 

The other rooms manage to cool down to anywhere between 20-24.... Some better than others and some faster than others.

 

I'm totally happy to keep things at a temperature around 26-27... but if I allow temperatures at that level the humidity is always over 60 and usually closer to 70.

 

 

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7 hours ago, dia1 said:

The current outside humidity in BKK is 62 and the temperature is 32... Yet inside one room in my house, I am reading humidity of 63.... a little higher than outside, despite the AC being on and sending in cool air.

Please be aware that when you cool down, the humidity rises. So, if you have 32 degrees and a humidity of 62 percent outside, and you cool down to 25 degrees indoor, the indoor humidity will rise to 96 percent!

 

You will find a humidity calculator here:

https://www.lenntech.com/calculators/humidity/relative-humidity.htm

 

Usually, fungus and mold spores shouldn't be a problem if you keep the humidity below 60 percent. It may be better to open all the windows to create airflow, as @pikao wrote. A closed room with a high temperature and humidity works as a petri dish; if you have airflow, you can have higher temperature and humidity without problems. If you must use aircon, try setting it on a higher temperature.

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For starters if you have a leak does the water pump run all the time if not then you do not have a water leak. Or shut every thing down and watch the meter if it continues to turn you have a water leak. if you had a roof leak it should have shown up by now by discoloring the cieling in the top room.

You did not mention on what setting you set your coolers but you need to set them on the lowest temp. they have to number one cool the place and to evacuate the moisture. and yes you need to shut the doors.

check the drain pipe off the evaporators and see how much water is draing out. It should start drying out soon with the end of rainy season, that should help. Also where is your house built maybe on an area where they get a lot of ground water.

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2 minutes ago, moe666 said:

Or shut every thing down and watch the meter if it continues to turn you have a water leak

The leak I had did not show the water meter moving at all...you can test to see how much water can actually pass the meter without it registering  by  letting a tap drip  it can be quite a lot if left on 24/7

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10 hours ago, farang51 said:

Please be aware that when you cool down, the humidity rises. So, if you have 32 degrees and a humidity of 62 percent outside, and you cool down to 25 degrees indoor, the indoor humidity will rise to 96 percent!

Relative humidity VS dew point    haven't found an explanation that makes sense to me yet.

 

Quote

The dew point is the temperature the air needs to be cooled to (at constant pressure) in order to achieve a relative humidity (RH) of 100%. At this point the air cannot hold more water in the gas form. If the air were to be cooled even more, water vapor would have to come out of the atmosphere in the liquid form, usually as fog or precipitation.

The higher the dew point rises, the greater the amount of moisture in the air. This directly affects how "comfortable" it will feel outside. Many times, relative humidity can be misleading. For example, a temperature of 30 and a dew point of 30 will give you a relative humidity of 100%, but a temperature of 80 and a dew point of 60 produces a relative humidity of 50%. It would feel much more "humid" on the 80 degree day with 50% relative humidity than on the 30 degree day with a 100% relative humidity. This is because of the higher dew point.

So if you want a real judge of just how "dry" or "humid" it will feel outside, look at the dew point instead of the RH. The higher the dew point, the muggier it will feel.

 

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24 minutes ago, johng said:

Relative humidity VS dew point    haven't found an explanation that makes sense to me yet.

This is a bit better than your quote, but still ... https://www.theweatherprediction.com/habyhints/190/

 

I found a better calculator which also displays the risk for mold at different temperatures/humidity/dew points: http://www.dpcalc.org/

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