Do you know the ideal humidity for your hardwood floors and how to manage humidity to protect your investment? We were fortunate to bring together a panel of building, air systems, and flooring experts to discuss key information to know about how water and water vapor enter homes and the built environment generally, what we can and should do (and not do) about this intrusion, and also what the ideal conditions are for our wood floors and other furnishings.
If you’d like more information, check out the Humidity, Hardwoods and Homes video or our Rate It Green discussion, Humidity, Hardwoods and Homes - The Building Science Approach to Protecting your Investment, for key concepts and conclusions.
A key lesson from this presentation is that we need to protect the floors under our feet at the same time we protect the air we breathe. What’s really interesting is that when it comes to controlling humidity, many of the same key concepts are relevant for people and building materials, and the equipment and actions we need are largely the same.
It turns out that the ideal humidity range for wood is the same as for human comfort and health, 30-50% humidity. The ideal temperature is between 60 and 80 degrees. In these conditions, wood moisture content will be about 6 to 9%. It’s important to maintain these conditions as closely as we can, as repeated cycles of wood absorption and release history the shape of wood.
As Brett Miller of the National Wood Flooring Association (NWFA) is points out, "Wood flooring is a barometer of everything that is happening in that home from an environmental perspective,” and a barrier we’ve invested in and should protect. Brett also reminds us that wood flooring is very visible, once of the first things we see and something we all walk across. Wood shows us when humidity is extreme, as it expands when it absorbs moisture and shrinks when it releases moisture. If a home is too dry, the wood will crack and split, stretch/gap and possibly experience finish delimitation. If a home has too much moisture, wood can swell, cup, and buckle. However, it’s a good idea to maintain optimal indoor air quality conditions, including humidity, before we see these effects and distortion or damage has occurred of course, whether to flooring, furnishings, furniture, doors, or woodwork.
Key topics covered include:
All wood contains some moisture. Where a living tree is 30-200% moisture, the wood of course must be dry enough to maintain a consistent physical property to be used as a flooring product. How do we find the right balance, and what are the ideal interior conditions for wood? It’s important to understand that the moisture content of wood depends on the amount of moisture in the air, which is known as relative humidity, or RH. In a high RH environment, wood absorbs moisture, and in low RH wood releases it. Joseph describes air with low RH as “thirsty.” It will pull moisture from anything around it that has humidity. For wood this can be cracking and checking. For people, this can mean pain and itchiness in heir eyes, nose, and throat. Another result of low RH is that viruses can become more infective, as they hang in the dryer air longer. Additionally, less moist air can lead to static shock, which can even damage electronics.
RH that is lower than ideal also causes problems. Wood can swell or rot, as we’ve discussed. But mold, mildew, dust mites, and termites thrive in RH over 50%. As for human comfort, a lower temperature without lower humidity creates a cold and clammy feeling that is not comfortable.
Keep in mind that one of the toughest variables in predicting performance is… people. Ask how a home will be lived in, and what the cooking, cleaning, bathing, and laundry habits are likely to be?
And finally, it’s important to monitor conditions. A lot of HAC equipment is “set and forget,” but only measurement will show us when something is amiss.
Wood flooring performs its best given the right, consistent combination of RH, temperature, and moisture content. There are of course other benefits to proper humidity control, including better indoor air quality to support human health, increased comfort, the preservation of other furnishings and building materials, odor reduction, and pest and mite control.
Fortunately, people and wood flourish in much of the same ideal range - 30-50% humidity. The ideal temperature for wood flooring is between 60 and 80 degrees. In planning tighter structures, the idea isn’t to stop air and moisture from coming into our buildings, but to properly control and condition this air in order to maintain healthy conditions, operate to meet our goals as efficiently as possible, and to preserve our investment.
Thank you to our amazing "Humidity, Hardwoods and Homes” Panelists:
Joseph Hillenmeyer
Senior Channel Marketing Manager
Aprilaire
National Wood Flooring Association (NWFA)
Brett Miller
VP of Technical Standards, Training & Certification
Matt Hoots
President
Sawhorse, Inc.
To learn more about Aprilaire, visit their Rate It Green profile:
https://www.rateitgreen.com/green-building-directory/sustainable-building-companies/aprilaire-a-division-of-research-products-corp/7888
For additional information about humidity and ventilation:
Whole House Humidity Control - Dehumidification and Humidification, with Aprilaire (Video)
An Introduction to Aprilaire and Whole House Air Quality Systems (Video)
VIDEO: A Look at How ERVs Work with Panasonic, How 80% Efficiency Might Work in Practice
Air Filtration at the #1920sMakeoverATL Showhouse - It Can Only Get Better from Here (Video)
Exploring Whole House Filtration and Particulate Matter, with Aprilaire (Video)
Air Filtration at the #1920sMakeoverATL Showhouse - It Can Only Get Better from Here (Video)
VIDEO: Spot Energy Recovery Ventilation (ERV) - Designed for One Location (vs Whole House)
Reviewing the Top Benefits of Healthy Air at Home, with Aprilaire (Video)
Walking and Talking about Fresh Air and Ventilation with Green Building Expert Matt Hoots - and Oliver
Green Building Myth Busting: Natural Ventilation - Do Your Walls Need to "Breathe?" (Video)
Your House May be Making You Sick!
What is the ideal humidity needed to help maintain hardwood flooring? (Q&A)
Thank you to Southface Institute for sharing visual explanations to support with Matt Hoots' presentation.
Date: December 20, 2025
Author: Rate It Green Team
Wood Flooring
