During the heating season, most of us fight the chill in our homes with central heat or wood-burning stoves—all equaling a lot of heat, and not necessarily a lot of moisture.
Given winter is a low humidity time of year, it’s easy to fall below the 35% Relative Humidity (RH) level, optimal for the wellbeing of your wood floors, walls, wood fixtures, and, well, you—according to our technical director, Nate Elbrecht.
So what is Relative Humidity? How does it affect your home, and how do you maintain proper RH levels to ensure your home (and your health) is off to a great start in 2020. I went to Nate for some answers.
Relative Humidity: Don’t Let it Harm Your Floor
Let’s dig into some fun and basic science.
Wood is hygroscopic—it’s always looking to reach an equilibrium of moisture. To the naked eye, it may appear that not a lot is going on, but wood is always taking in or giving off moisture, depending on the condition of the wood as it tries to achieve that equilibrium. And this is where RH, a measurement of water in the air, comes in.
RH has an inverse relationship with temperature. On a chilly day, if the humidity outside is 30%, then the air in the house will warm up and expand, and the RH falls as you heat up the air. This means two things for your floor:
- When the RH falls below a certain point, the wood floor will give off moisture. Too much and your floors can buckle.
- During the heating season, without moisture being introduced back into your home’s environment, your humidity level will drop considerably. Too little and your floors can crack or split.
To measure and maintain the RH in your home, you just need a hygrometer. You can pick up a trustworthy device at any big-box store, like this one, or if you have an adventurous child, you can always construct one on your own with horse hair, like Nate did for an elementary-school project. However, we would likely recommend the big-box store.
Can RH Levels Be Too Low or Too High, and Does That Effect Your Floor?
Indeed, it does.
At Real Wood Floors, we sell two types of flooring: solid and engineered. Both types of flooring are made for environments with 35-55% Relative Humidity. The only exception occurs when you live in a very dry climate such as Nevada, where the RH stays within a low range and you acclimate your flooring to that level.
In the winter, if you are tempting fate and your RH levels fall below recommended levels, then the wood contracts. With solid flooring, you get seasonal gapping, gaps between your wood planks. This seasonal gapping also happens with engineered flooring, but the divergence is a lot less.
Other side effects of a too-dry environment occur when the wood shrinks, and it causes those annoying creaking and popping sounds in your floor.
In Dry Winter Months, How to Increase Your RH
In the wintertime, there are a number of ways to increase the RH in your home. Your goal is to increase moisture in order to raise the humidity, so cooking, washing dishes, showers, and doing laundry—all of these activities can add moisture to the environment. If those activities don’t bring the RH up to 35%, then you want to add moisture from a humidifier in the home.
Hitting the Right Relative Humidity in Your Home Isn’t Just for Your Floors
Beyond wood floors, RH is also important for any wood in the home. Furniture, windows, walls, even the framing of the house--anything composed of wood will contract or expand, if you don’t achieve proper RH levels.
In addition to maintaining your wood floor and household wood products, other good reasons to have your house between 35 and 55 include:
- Your overall health. The human body naturally wants some humidity in the air. Without proper moisture in the air, we can get itchy skin or have sinus issues. So you and your family are better off with the appropriate moisture level in your home.
- The prohibition of bacteria, viruses, and mold. When RH levels are ultra-low or ultra-high, it provides a welcome scenario for the unpleasant growth of bacteria, viruses, and mold.
Too Much Science? Too Much Horse Hair? We Can Help
If this is overwhelming, we’d love to help. Call us or email.