Determining Optimal Wintertime Indoor Humidity
joenorm
| Posted in General Questions on
Hi All,
Newly built house and experiencing our first taste of the heating season(zone 4C)
I installed wood flooring and I can hear it popping as it shifts around the more the heat is on. I use a combination of a single zone mini-split and woodstove.
I have never thought much about indoor humidity, but my concern is mainly treating the floor as best I can, I don’t want to do any damage by drying it too much over the season.
Is it wise to run a humidifier? Also, is there a Hygrometer that people recommend buying? And what is the desired indoor humidity in a perfect world?
thanks
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Replies
You can run a humidifier, but you have to be careful. Excessive indoor humidity can cause a lot of problems inside of walls, including mold growth. 40% is usually considered to be a max for indoor humidity, lower is safer. I wouldn't want to get much below 20-25% though. The colder it is outside, the lower you want your setpoint to be to avoid moisture problems, although with better insulated/sealed walls and windows, the safer you are with higher humidity levels.
Most consumer type hydrometers are pretty inaccurate. I've used the accurite ones (and still do), mostly because they are cheap and the wireless monitoring can be useful. I have some sensors based on a Humirel sensing element that I trust, but those are custom monitors that I built from scratch for this purpose. Your best option is to use one of the cheap sensors, let it sit outdoors for a little while, then compare what it says to what a nearby NOAA weather station says. This will get you an offset that lets you sanity check your cheap sensor before you start "trusting" it.
Bill
Hi Joe,
I think you will find this Q&A thread of interest: Recommended Indoor Humidity Levels. And these articles should prove helpful: Measuring (and Understanding) Humidity, and What Is the Ideal Relative Humidity in Winter?
If you're not measuring humidity you're shooting blind.
During construction, did you measure infiltration with a blower door test? Houses that are dry in the winter usually are leaking a lot of air. In a tight house the humidity that occupants produce will keep it comfortable or even in need of ventilation.