In the midst of a whole home remodel, just outside of College Station. The AC unit is getting installed next week. It's a Lennox EL18XCV. I decided to add a whole home dehumidifier.

I've heard plenty of times that a Variable AC unit will handle the humidity in a home just fine. From what I've read, the variable AC units can get relativity humid to around 50-55%. In my opinion, that's on the high end of the suggested range, if not slightly above. I'd like to keep the house around 35-40%.

What say you? Am I going overkill with the dehumidifier?

Who (vendor) are you using?

I'd have to ask my GC.

EDIT: We originally ordered the XC20, but no end in sight on when we might get it. Got a call yesterday saying we could get the EL18XCV in our hands next week. 1 SEER rating and 5 dB sound difference. I said 'Make it happen.' Next month will be the one year date of this remodel, and I'm starting to get antsy.

Definitely can't wait so will ask these questions with vendors coming to quote. Thx.

vmiaptetr said:

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In the midst of a whole home remodel, just outside of College Station. The AC unit is getting installed next week. It's a Lennox EL18XCV. I decided to add a whole home dehumidifier.

I've heard plenty of times that a Variable AC unit will handle the humidity in a home just fine. From what I've read, the variable AC units can get relativity humid to around 50-55%. In my opinion, that's on the high end of the suggested range, if not slightly above. I'd like to keep the house around 35-40%.

What say you? Am I going overkill with the dehumidifier?

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35%?! You're gonna have to serve steaks quick before they turn into beef jerky.

I'll just put some ketchup on it to bring it back to life.

vmiaptetr said:

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In the midst of a whole home remodel, just outside of College Station. The AC unit is getting installed next week. It's a Lennox EL18XCV. I decided to add a whole home dehumidifier.

I've heard plenty of times that a Variable AC unit will handle the humidity in a home just fine. From what I've read, the variable AC units can get relativity humid to around 50-55%. In my opinion, that's on the high end of the suggested range, if not slightly above. I'd like to keep the house around 35-40%.

What say you? Am I going overkill with the dehumidifier?

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Are you doing foam insulation in the attic and walls?

Yes. That includes the garage.

vmiaptetr said:

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Yes. That includes the garage.

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Then, yes, you need a dehumidifier that also brings in outside air. The AC system is only going to dehumidify when it is running in cooling mode. During the winter the foam is going to trap all of the heat and humidity and you will have waterfalls running down your windows.

I highly recommend the UltraAire brand with hanger kit. I installed an XT105 a couple years ago. It makes a big difference in the "shoulder" months (I can keep it between 40-45% humidity during the spring and fall), and is quieter and more energy efficient than the unit I used to run in the hallway that had to manually dump the catch bucket on once a day. It includes a makeup air connection for drawing in outdoor air controlled by a motorized damper (extra). I've opted not to use that feature since I have a leaky 60 year old house, but it would be a great feature for an airtight foam insulated build.

Got the AC and Dehumidifier installed this morning. Lowest the dehumidifier can be set is 40%, and that's considered middle range for suggested relative humidity (from what I've read). I got it set to 45%. We'll see how it is 24 hours from now.

Where are you reading that? Most I've seen is around 50%, and none of that is really specific to our area.

When I had mine installed the various companies I talked to said 55-60%.

ETA: ours is at 55%ish and we've never been uncomfortable

It was just a quick google of "optimal relative humidity in house." The first thing that pops up is an article from Lennox that references a write-up from the Mayo Clinic on humidity in the home.

https://www.mayoclinic.org/diseases-conditions/common-cold/in-depth/humidifiers/art-20048021

I have no doubt that 55-60% is comfortable for our area. That's a significant decrease from what we experience outside during certain times of the year.

vmiaptetr said:

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In the midst of a whole home remodel, just outside of College Station. The AC unit is getting installed next week. It's a Lennox EL18XCV. I decided to add a whole home dehumidifier.

I've heard plenty of times that a Variable AC unit will handle the humidity in a home just fine. From what I've read, the variable AC units can get relativity humid to around 50-55%. In my opinion, that's on the high end of the suggested range, if not slightly above. I'd like to keep the house around 35-40%.

What say you? Am I going overkill with the dehumidifier?

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. Why would you think 35% is comfortable? Also, if you have wood floors kiss them goodbye now and enjoy the extra cracks in your walls.

htxag09 said:

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Where are you reading that? Most I've seen is around 50%, and none of that is really specific to our area.

When I had mine installed the various companies I talked to said 55-60%.

ETA: ours is at 55%ish and we've never been uncomfortable

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30-50% target per EnergyStar.
https://www.energystar.gov/products/appliances/dehumidifiers/dehumidifier_basics

Yeah, 60% is not a good target. General consensus is >55% risks supporting fungal/bacterial growth. I suspect HVAC guys saying 60% don't want to be bothered with call backs when the equipment they installed in the building envelope doesn't adequately dehumidify.

I have it set at 45% right now. My plan is to just have it set in the middle @ 40%.

Single digit RH in ABQ during Winter and into June.

40% is really humid during the monsoon season.

I have a standalone dehumidifier up in the attic and even with that I'll do 50% on a good day in the summer. The joys of living in the southeast.

Any update ? How well did 45% workout ?

Took a bit to get everything correctly running. The original thermostat installed was only for a two-stage system, and it wasn't communicating the AC and dehumidifier.

Got the right thermostat installed. All the units are communicating, and after a 24 hour period, the house was staying at a constant 45% relative humidity. 75 degrees feels considerably cooler with it being drier. I may drop it to 40%, but I'm pretty comfortable where it's at.