Is humidification requried in a northern climate?
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| Posted in Mechanicals on
I plan to build a new house in west central Wisconsin and I’m wondering if a humidifier is necessary. I plan to have a fully ducted ventilation system probably with an ERV (architect recommended) although the HVAC contractor believes that an HRV should be used (I’m forwarding him the HRV or ERV? posting).
Would an ERV be sufficient to keep the moisture levels sufficiently high during the dry winter months? The wife wants a monstrosity and there are only three of us living in it if that is useful.
Thanks, Tom
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Replies
Tom,
I don't know what kind of monstrosity you mean -- the one you say your wife desires -- but it doesn't sound good.
If you are building a new house, you don't need a humidifier -- unless you have some rare art works or very valuable musical instruments.
The most common reason for dry indoor air during the winter is a high level of air leakage. (Outdoor air is very dry during the winter, so if your house is leaky, your indoor air will be dry.) If you can convince your builder to build a tight house -- verified by a blower-door test, of course -- you won't need a humidifier.
Thanks Martin. By monstrosity I mean that it will be much larger than what we really need otherwise it will be a very beautiful and functional home. Sadly it causes me significant anxiety knowing that we will be consuming resources that could be used in much better ways.
I have been learning an immense amount of information from greenbuildingadvisor as well as similar sites and I have been applying it to the plan that my architect has been creating so I expect that the house will be very energy efficient assuming that the contractors can perform to my expectations when building it.
ERVs might suffer freeze damage in central WI climate- it's kind of on the edge of where ERVs are useful in summer anyway. But for conserving winter moisture, fuggedaboudit- not much use there.
In a large/very large tight house with only 3 people living in it (say, 1500-2000 square feet per person) standard ASRHAE ventilation rates are gonzo-high (unless you all are chain smoking stogies or something. :-) ) Dialing back the HRV's ventilation rate to a bare minimum conserves moisture- in smaller homes you can usually just run them under dehumidistat control set to 30-35% and it will keep up with the indoor air pollutants (not that humidity is the best measure of indoor air pollution.)
Rather than an active humidifier, keep a bunch of houseplants- grow your own ficus forest or something, which will add moisture to the air, while cleaning up some of the indoor air pollution, and run the HRV under dehumidistat control If that approach still leaves you with nose-detectible VOCs or cooking odors hours & hours after you burned the toast you may need to bump the ventilation rate.
In any tight house of any size you have to get religious about running kitchen & bath ventilation to purge high-moisture or high air-pollutant areas at their source, which will allow you to run the HRV at a lower average ventilation rate and still maintain good indoor air quality.