Humidity Gauge

Does anyone ever test for humidity?

I know this is not part of the SOP but was just wondering.

It would be nice to have for homes with a basement to see if there humidity levels were high.

I have a gauge in my own home & keep my humidity between 35 to 45%

By the way Professional Equipment has a 50% off sale on some nice items.

Yes I take a relative humidity reading when warranted.

Spend the $$ and buy a good one.
The cheaper ones aren’t worth their weight and can give you false readings.

When I get into a house I take a RH%, mostly for conversation and figure how sick I will be in a few hours. I did a home inspection where the house was rh 72%, had mold on walls, and mushrooms growing out of the carpet. Since the air was moist, the spores had to be thick. I felt like I chain smoked a pack of cigs when I was done.


$20.00, works fine. I do outside, home interior and basement/crawlspace. Outside provides a baseline, interior and crawl readings can alert you to moisture intrusion you can’t see.

The outside RH can easily change by 20-50% from morning to afternoon daily or with a change in weather over a day!! IMO, it’s not a reliable baseline.

In your opinion Brian , what is???

Knowing the average wood moisture contents for homes in your area from season to season would be a start. Plus using the chart of wood moisture content when exposed to high (70-80%+) continuous air RH’s would allow one to make an educated recommendation that if conditions continue or aren’t changed longterm rot/fungal growth may begin.

I agree with Brian. There are way too many variables when determining a base line RH level.
Time of day is one huge factor.

Oh, just some extra information. On the house that had a 70% RH, everything came up ‘alarm’ levels with my moisture meter. Having the RH helped me explain how I could not differentiate between the past like damage stains and an present water damage.


You have a good point there Brian, but I find that if I do it on every home I start to get a feel for humidty levels. The readings I get are not something I’d typically use in a report but a high one inside makes me pull out the moisture meter and poke around.

Outside humidity levels here seem to average between 25% and 40% but wood levels measured in log home exteriors are typically barely measureable with the surveymaster which has about 10% as the bottom of its range. Even with the conversion chart, wood moisture levels don’t appear to mirror average realtive humidity.