Humidity Control in Cold, Humid Climate
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| Posted in General Questions on
We have a 1000 SF vacation home in coastal Maine that is experiencing humidity problems. We have no mechanical ventilation in the house. In the summer, it needs no AC and the windows are kept open. In the winter, we rely on hydronic radiant heat. Humidity is very high year round (about 80%), but a major concern in winter when we see significant condensation on our windows. We are considering installing an ERV unit but would love feedback on the simplest way to add both fresh air and humidity control, mostly in winter.
Thank you!
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Replies
Air at 72F and 80% RH has a dew point of 65F. I can guarantee you that no place in Maine regularly has a outside dew point of 65 in the winter, because no place in Maine has outdoor temperatures that high in the winter, and the dew point can never be higher than the temperature.
What that means is that humid exterior air leaking in does not account for the humidity you are experiencing in winter. I can think of two other possibilities: one is that something inside the house is generating excessive humidity. The other is that there is moisture leaking into the house somewhere, probably either in the basement or through the roof.
Tell us more about the house: how old is it, what is the construction like? Is it well insulated? Is it tight or drafty? What's the basement like?