If your floors have started creaking like a haunted house, or your doors suddenly don't want to close properly, you may be worried that the foundation of your home is cracking and settling. Don't panic — it's probably just drying out.

As the weather cools and you flip on the heat, your home's humidity drops, and that has a direct effect on all the wood in your house, from floors to door frames.

Why this actually happens

Wood is constantly trading moisture with the air around it. During the summer, it swells when the air is humid (kinda like my hair!), and it shrinks when the air is dry.

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So when you turn on your furnace for fall and winter, that's exactly what happens.

(MORE: Find the best humidifiers for winter)

Winter heating lowers your indoor relative humidity while the absolute amount of moisture in the air stays about the same, according to Oregon State University's Extension Service.

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Wood can shrink by about 8% across the grain, OSU Extension also said. Their experts say that means a 10-inch-wide floorboard can lose four-tenths of an inch when it dries out, a gap you'd definitely feel under your feet.

Is it settling or just drying out? Here's how to tell

Experts say gaps created by normal seasonal movement will close back up once humidity returns to normal, while structural settling doesn't reverse and it can show up as diagonal cracks in your wood or walls.

(MORE: People are watering their houses — here’s why it works)

They also caution against reaching for a plane every time a door sticks in winter. Shave too much off, and the door can end up too loose once the wood swells back up in the humid summer months.

The humidity range to aim for

Most smart home thermostats have a function or gauge that can tell you the humidity in your home. The National Wood Flooring Association recommends keeping indoor relative humidity between 30% and 50% year-round, at a temperature of 60 to 80 degrees, specifically to protect wood flooring.

Getting into that range usually means adding a humidifier. A whole-home humidifier, including the unit and installation, typically runs $500 to $2,500, according to Carrier and Angi's 2026 cost data.

(MORE: Homeowners, do these 17 things before winter)

But that could be significantly cheaper than ripping up or repairing expensive floors, doors and door frames.

So before you call a foundation contractor over a creaky floor or a stuck door this fall, check your home's humidity level first. It might be the only fix you need.