Is it cheaper to run a dehumidifier than an ERV in winter?
srivenkat
| Posted in Energy Efficiency and Durability on
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.
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Replies
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.
Of course it would be even cheaper to lower humidity by using an efficient wood stove.
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
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.
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.