Options to reduce humidity level in house?

2,054 Views | 19 Replies | Last: 1 yr ago by stu.pidarse
FDXAg
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AG
Have a two-story 3,000sq house with a single stage AC unit. Wish I had been able to afford a dual stage unit 5 years ago when I had the system replaced, because i'm dealing with uncomfortable humidity levels in the house during the summer. What are my options? Could I use a couple portable dehumidifiers to help? I didn't know how much hot air they expel or if they could be a viable option.

I've heard of whole home dehumidifiers but I have no idea how much that could cost to buy and have installed. Would I be looking at $2k to $3k?

Any other ideas? I know we have an old dryer that probably needs replacing as it's very inefficient. We have to run up basically all day long on laundry day. Didn't know if that's something that could drastically help.
Give Us Room
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AG
This might not be your issue, but I thought I would mention it. We moved into a new construction home about a year ago. It was REALLY humid in areas. We brought out the A/C guy and he said that there are now vents that pull in air from the outside into the A/C system. How that makes sense in the Houston area, I will never know. But we had him close it and that problem went away...
TexAg1987
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Check with your A/C tech if they can slow down the fan on your indoor unit.

If the air moves slower over the coils it will pull more water out of the air.
Martin Q. Blank
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TexAg1987 said:

Check with your A/C tech if they can slow down the fan on your indoor unit.

If the air moves slower over the coils it will pull more water out of the air.
And may freeze up the coil.

Program your thermostat to have a delta of 2 degrees instead of 1. You A/C will run longer.
FDXAg
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AG
One thing I'm trying to figure out.... As I'm reading 2 different things on the internet.

With a 2 story house, I see every HVAC website mention that you should have a 2 degree temp difference in the upstairs and downstairs thermostats. So, in the summer, should the upstairs be set 2 degrees colder than the downstairs? Or the reverse?

Logic makes me think that in the summer the upstairs should be set at your "desired" temperature and then you set the downstairs 2 degrees warmer, because the cold air from the upstairs will eventually fall down to the lower level. AKA in summer set upstairs to 77 and downstairs to 79?

Unfortunately for every website that says this, there's another that says the opposite. They claim in the summer you set the upstairs to your desired temp (77) and then set the downstairs 2 degrees cooler (75). This one doesn't make sense to me
txag2008
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AG
That's not really applicable for you since you only have 1 unit (and presumably 1 stat).

You remove humidity from the air by running your A/C, as warm air moves across a cool coil moisture (condensate) is pulled out.

Unit sizing can cause issues. If it's oversized it'll run for shorter durations of time and not do a good job of dehumidifying. Otherwise, make sure your coil is clean and that it has a proper charge.
FDXAg
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AG
Ahh, ok. I only have the one unit but it is a dual-zone and I have 2 thermostats, 1 downstairs and 1 upstairs. So I didn't know if that made a difference.

Unit is a 5-ton for a 3k sqft house. I remember getting multiple bids and all said that was the correct size, so hoping it's not oversized.

Would it help humidity levels to get a smart thermostat that slows down the run cycles and gives the option to have the fan run continuously for a set amount of time every hour?
Agzonfire
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Buy a dehumidifier? Can't you get one that ties into a drain?
tgivaughn
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AG
I have to enter a simple humorous solution that will work but not expecting it to be popular, just super EZ.

1. Best Buy will install a new dryer presto chango & cart the old one off, install also a fresh, clean vent to outside (hopefully a very short run!). Get a more expensive & pest-deterrent outside vent perhaps, leak & backdraft free.

2. Amazon & others will deliver a window AC with features like SEER and dehumidify factors/options for reasonable price. This would be installed upstairs but able to throw air out into downstairs (it's taking the warmest air that rises & throws cool, dry air that sinks.) The Amazon brands that have performed well in this fashion (past - we have new HVAC sys now) =
https://www.amazon.com/gp/product/B01D3FOMHK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
You may elect a larger one by guestimate. Run it all the time on normal, then try other phases like the dehumidify phase. Rule of Thumb: 20 guests & their humidity = one ton AC required extra in a HVAC comfortable house hosting a party.

3. You might camp out in the attic sometime to explore any leaks in ductwork, then solutions to them; certainly even with no leaks, cheap insulation over ducts is an investment that always pays dividends. A local church's high utility bills & humidity problems were solved in this manner. Its new HVAC was sucking loads of attic air - RA ductwork in their case.

Please let us learn from your report later on what worked for you ... and in what area/zip code.
IMHO and am sticking to it
Jason_InfinityRoofer
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FDXAg said:

Have a two-story 3,000sq house with a single stage AC unit. Wish I had been able to afford a dual stage unit 5 years ago when I had the system replaced, because i'm dealing with uncomfortable humidity levels in the house during the summer. What are my options? Could I use a couple portable dehumidifiers to help? I didn't know how much hot air they expel or if they could be a viable option.

I've heard of whole home dehumidifiers but I have no idea how much that could cost to buy and have installed. Would I be looking at $2k to $3k?

Any other ideas? I know we have an old dryer that probably needs replacing as it's very inefficient. We have to run up basically all day long on laundry day. Didn't know if that's something that could drastically help.


A single stage unit will work just fine if it's sized properly and set up properly. Unfortunately, most AC companies use a 'rule of thumb' which is not only outdated, but lazy as hell. The same companies don't do much in terms of setting up anything either, which means your system may be defaulted. Generally the contractor grade stuff I see has a 4 ton air handler mated to a 2 ton system all defaulted out. It runs like crap and is humid inside until they match the settings properly so it runs like it's supposed to. Have a qualified tech check all of this.

If your unit is actually oversized, then you may not be able to get the humidity levels down. If you live in houston, and its 100 degrees outside, and the inside of your house is 72, then your system is massively oversized. In this case, you will need to supplement this with a dehumidifier. I have been quoted up to 7,000 LOLDOLLARS for one in some cases. You can thank Karen for whining about her AC not keeping up with extreme temperatures. Design temps in the region are a lot lower, so if youre AC is running all day long nonstop in this heat, then its doing what it's supposed to do provided its up on maintenance.

As for the dryer, if your dryer is ducted through the roof, then you need to check that duct work for lint. If its not ducted through the roof, then you need to check that duct work for lint. Nearly every roof I replace has a clogged or nearly clogged exhaust vent. I will generally reach down as far as my arm will go and clean it, but the elbows and reducers all the way to the dryer need to be freed. Once you verify that its clear, your dryer will perform a lot better. If its clogged, then you're also on your way to tripping the thermal fuse on your dryer. It is not resettable and you will have to replace that.
aggiechick
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Curious to what is the answer to the two degree question. Should the upstairs unit be the desired temp? And the downstairs be hotter or colder?

Or downstairs be the desired temp? And upstairs is hotter or colder?
TexAg1987
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During the summer, set your upstairs thermostat to your desired temperature, and the downstairs unit two degrees warmer. During winter, set the downstairs temperature to the ideal level, and upstairs two degrees colder.
Lobster Twins
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AG
Maybe not your issue but we had awful humidity levels. I eventually got a ladder and went up into the air return where I found a whole sheet of drywall had come loose. It was sucking straight attic air into the AC. Several AC companies didn't find it and couldn't explain other than maybe time to replace the system. Fixed it for us instantly. Hope you find a solution.
aggie_wes
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AG
As for your portable dehumidifier question, they are loud and put off a lot of heat. You also need to drain it to a point lower than the unit. I don't think it will be a viable option unless your room gets cold but still humid. Then maybe.
JP76
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FDXAg said:

Have a two-story 3,000sq house with a single stage AC unit. Wish I had been able to afford a dual stage unit 5 years ago when I had the system replaced, because i'm dealing with uncomfortable humidity levels in the house during the summer. What are my options? Could I use a couple portable dehumidifiers to help? I didn't know how much hot air they expel or if they could be a viable option.

I've heard of whole home dehumidifiers but I have no idea how much that could cost to buy and have installed. Would I be looking at $2k to $3k?

Any other ideas? I know we have an old dryer that probably needs replacing as it's very inefficient. We have to run up basically all day long on laundry day. Didn't know if that's something that could drastically help.



Have you placed a humidity gauge Inside to measure actual humidity ? If so what readings are your getting ?


Are your thermostats currently set on Auto for the fan ?
JP76
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TexAg1987 said:

Check with your A/C tech if they can slow down the fan on your indoor unit.

If the air moves slower over the coils it will pull more water out of the air.


You can also get a more restrictive filter such as the higher rated allergy ones and this will slow down the airflow over the coil some
FDXAg
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AG
I thought about the more restrictive filter idea. So that would likely cause the system to run a little longer each cycle? Right note I'm using the cheap fiberglass ones because years ago I had read that the higher MERV filters put a strain on the system by reducing airflow.

Bought a cheap humidity meter from Amazon and readings are around 55-60% in the house. Have another meter coming today so I can compare the readings and make sure the devices are fairly accurate return each other.

Fan is set to "auto".

WorthAg95
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AG
Ecobee smart thermostat with humidity control… start here
JP76
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The cheap fiberglass one while least restrictive. will all make your coil filthy over time. Try one of these and see what the humidity reading does


https://www.lowes.com/pd/Filtrete-1500-MPR-Ultra-Allergen-Common-16-in-x-25-in-x-1-in-Actual-15-7-in-x-24-7-in-x-0-7812-in-Electrostatic-Pleated-Air-Filter/3514358


Or you can have a tech try dropping the blower speed down but I would still run a better filter such as this over cheap fiberglass

https://www.lowes.com/pd/Filtrete-1085-MPR-Micro-Allergen-Extra-Common-20-in-x-25-in-x-1-in-Actual-19-6-in-x-24-7-in-x-0-8125-in-Electrostatic-Pleated-Air-Filter/3134429



stu.pidarse
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More restrictive air filter will reduce airflow if it's a PSC blower. If it's a variable speed blower it may slightly or not at all reduce airflow depending on how its programmed.

There is a good chance you can reduce the airflow and it will help reduce humidity. Most systems today have control that prevents freezing of the air coil down to about 70% of rated airflow.
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