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Is it cheaper to run a dehumidifier than an ERV in winter?

I am in zone 5A and I have a problem of excess humidity in my ICF home with no abnormal sources of moisture (5 occupants of a 2150 sft home with a full basement). This results in condensation on the wall of windows facing a pond on the north.

Since a dehumidifier will also dump heat into the home helping my all-electric furnace heat the home, I am wondering if it would cheaper to run the dehumidifier than to use an ERV to lessen the humidity in the home. I realize in the latter case, there's some loss of sensible heat that the electric furnace would then have to compensate for.

TIA.

Asked by Venkat Y
Posted Aug 29, 2014 4:17 PM ET
Edited Aug 29, 2014 4:19 PM ET

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5 Answers

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1.

You still need some ventilation in winter, but for simply lowering the humidity during the heating season a dehumidifier would be more energy efficient overall, quite a bit more if you are heating with resistance elements rather than a heat pump.

Depending on your local climate and house construction you may need to pull the humidity down to 35% RH or lower to be protective of the house itself.

Answered by Dana Dorsett
Posted Aug 29, 2014 5:17 PM ET

2.

Of course it would be even cheaper to lower humidity by using an efficient wood stove.

Answered by flitch plate
Posted Aug 29, 2014 8:09 PM ET

3.

Sounds more like you need a HRV installed. Condensation is typical in a tight home with poor air exchange or lack of bathroom and kitchen ventilation. Dew point sensors installed in lieu of fan switches in the bathrooms can also assist.

http://www.dewstop.com/

http://www.venmar.ca/39-air-exchangers-e15-ecm-hrv-new.html#!prettyPhoto

Answered by Richard Beyer
Posted Aug 29, 2014 10:52 PM ET

4.

Venkat,
Richard is right: if you are having problems with high indoor humidity during the winter, you want an HRV, not an ERV.

I disagree with Dana's advice. During the winter, lowering indoor humidity levels by ventilation is less expensive than lowering indoor humidity levels by operating a dehumidifier.

Answered by Martin Holladay, GBA Advisor
Posted Aug 30, 2014 6:43 AM ET

5.

ICF homes take about one year to dry out initially. Also, if there is no capillary break, concrete walls can wick water up from below grade.

Answered by Kevin Dickson, MSME
Posted Aug 30, 2014 2:08 PM ET

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