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Heating & Air Conditioning

system dehumidifier vs. 2-stage A/C

15 years ago

We have multiple HVAC systems in our new house, and as is common here, they are just basic builder grade equipment. As is also typical here, they are oversized and don't run nearly long enough to get the humidity to an appropriate level for the allergy sufferers in our family.

As soon as we close on the sale of another house, I plan to replace two main floor systems with higher SEER two-stage equipment. However, I'm wondering if for the walk-out basement we might be better off having a dehumidifier installed instead? My concern is that in the spring and fall when the A/C or heat don't need to run, we will experience high humidity as we did this spring, even if a two-stage A/C handles the humidity just fine in the summer.

I've read about "whole house" dehumidifiers, costing around $1,500+, that should handle the approx. 2500 SF in the lower level. That's a big savings over a new two-stage 16 - 19 SEER system, and would have the added benefit of dehumidifying the space when the temps are too mild to require heating or cooling. I'd replace the current equipment with a two-stage system once it reaches the end of its useful life, but sure wouldn't mind delaying that expense for a while.

Am I overlooking something? Is there a better way to handle the situation? Thanks.

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Comments (2)

baldloonie
15 years ago
A/C units only dehumidify when they are on. Lots of weather when they don't run much but you need dehumidification. That's why the whole house units are an advantage.

Also, check the specs on some of these 2 stage A/Cs. One popular model does poorly at moisture removal on low and not as good as their single stage models on high. So are you gaining anything? Most 2 stage units run 75-80% on low (though they say less) so not much diff between high & low.
rockmanor
Original Author
15 years ago
Baldloonie, would you mind sharing which model of 2 stage A/C performs poorly at moisture removal? We had American Standard's 18 SEER 2-stage in a previous house and were pleased. I seem to recall being told that the 4 ton unit we had ran at 50% for most of the time, going to full power only on the hottest days. The builder's HVAC guy fouled up the installation, so I brought in a company that American Standard recommended and they set things straight.
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