whole house dehumidifier installed in HVAC

have you tried a portable dehumidifier to see if it makes any difference?

I installed one myself recently in my mid- 90s built house. Really like it. Especially shines on days like today where outside temps are in the 70s and humidity is in the 80s.

Edited to add: not sure what installers would charge, and bet many don't have experience with them. Mine was just the cost unit, controller, and the install supplies(flex duct, take off, drain pipe, drain pan, and electrical wire).

Head over to hvac-talk if you want to read more about configurations and options.

I have the ultra-aire xt105h. It has it's own dedicated return but the supply feeds into the HVAC supply ducting so the dry air is pushed throughout the house. There's a butterfly check valve on that supply feed.

Sounds like you are a perfect candidate for a whole house dehumidifier - it is these transitional weather conditions in the Deep South that these units supposedly shine. I to plan to have one installed as well but haven’t gotten pricing yet, as I had planned to have it done when replacing my older HVAC, but I may have to re-think this.

The equipment cost is not particularly high (depending on size), and watching YouTube videos on their installation is simple pretty straightforward, particularly if an electrical outlet is located in the attic near where the unit will be placed. Only a guess, but I suspect or would hope installation cost would/should likely be about equal the cost of the equipment.

As another poster said, any post on the HVAC-Talk forum on this topic answered by “Teddy Bear” who is a guru (retired engineer who was instrumental in the design of the Aprilaire whole-house dehumidifiers) is very informative (pricing is not discussed on that site as per forum rules).

Should you get cost estimates and go forward with this, I hope you’ll update this thread.

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I want a dry house, dammit.

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I’ve been monitoring living area and attic humidity in my house 24/7 with a couple Bluetooth humidity/temp meters. for the past 1.5 years. Wanted to know what I’m dealing with before I replace my HVAC.

I can really feel the decrease in comfort level when humidity exceeds 55%, and the highest I’ve measured is 58% when AC is not operating in rainy weather. If your at 65% that’s almost unbearable - almost like having a broken AC.

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If your at 65% that’s almost unbearable - almost like having a broken AC.

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It's not unbearable--I lived for years without AC--but it certainly would help allergies, comfort level, etc.

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There's almost always an extra outlet in the AC closet.

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No AC closet....return register is in ceiling, in the middle of a hallway. Unit is in attic. Open plan house, so not very many convenient places to "hide away" a large capacity dehumidifier. I can't seem to find one that won't fail after a few years....literally the best rated one on Amazon was being recalled/bought back by Honeywell due to failures. If the local AC guys are clueless, I might try out the portable....or if I find a super good deal online.

I did it two years ago in November and it's been amazing. We put in a new 5 ton unit and added a 3 ton equivalent dehumidifier. The dehumidifier's exhaust empties into the A/C air return and will slowly increase the temp near the thermostat kicking on the A/C so the A/C will then pull the dryer air and circulate that. It's made a huge difference on the overall comfort of the house and while I can't quantify it I'm pretty sure the showers and tubs are much easier to keep mildew free. I keep the humidistat on about 53%.

Installed cost added about $2,300 to the overall cost of what we did to the project, including plumbing and pulling new power to operate the unit.

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Bought a 70 pint portable GE dehumidifier at Home Depot.....plugged it in yesterday. Amazing how much water that thing pulls out of the air. Haven’t yet hit the 24 hr mark, but it isn’t too loud. Planning to let it run until it actually reaches 50% humidity.....dunno how long it will take. Unit is rated for 1500 ish square feet, and I’ve got 2100....

Local HVAC guys didn’t know much about installing or performance of a whole house dehumidifier. So I’m using the portable until I find a service provider who has actually installed one.