Winter humidity is usually too low to need a dehumidifier
In most climates, you should not run a dehumidifier during winter. Cold air holds very little moisture, so indoor humidity naturally drops when outdoor temperatures fall—even with heating running. Most homes end up with humidity between 20 and 40 percent in winter, which is below the 30 to 50 percent range where mold and dust mites thrive. Running a dehumidifier when humidity is already low will only dry out the air further, making the space uncomfortable and potentially damaging to wood furniture, flooring, and your skin and respiratory system.
The exception is if you live in a warm, humid climate where winter temperatures stay above 60°F most days, or if you have a specific moisture problem in one room—a basement that stays damp year-round, or a bathroom where moisture lingers after showers. In those cases, selective use makes sense. But for the typical homeowner in a cold-winter climate, the dehumidifier should stay unplugged from November through March.
Key Takeaways
- Winter air is naturally dry because cold temperatures hold less moisture, so most homes do not need dehumidification in winter.
- Running a dehumidifier when indoor humidity is already below 30 percent can cause dry skin, cracked wood, and respiratory irritation.
- If your basement or crawlspace stays damp even in winter, a dehumidifier in that one space may prevent mold, but the rest of the house does not need one.
- Warm, humid climates where winter temperatures stay above 60°F are the main exception—humidity may remain high enough to warrant year-round dehumidification.
How winter heating makes the air drier
When you heat a home in winter, you are warming outdoor air that is already low in moisture. Cold air at 30°F and 80 percent relative humidity contains far less actual water vapor than warm air at 70°F and 50 percent relative humidity. The moment that cold air enters your home and is heated to room temperature, its relative humidity drops sharply—sometimes to 20 percent or lower—because the same amount of water vapor is now spread across warmer air that can hold much more.
This is why winter air feels so dry even though the outdoor air may have seemed humid before it was heated. Your furnace or heat pump is not removing moisture; it is straightforward warming air that was already moisture-poor. The result is that most homes naturally reach humidity levels well below what a dehumidifier is designed to handle. A dehumidifier works by cooling air to condense moisture out of it, then reheating it—a process that wastes energy when humidity is already low and can make the space feel even more uncomfortable.
What happens if you run a dehumidifier in winter anyway
Running a dehumidifier when indoor humidity is already between 20 and 40 percent will pull moisture out of the air and out of everything in the room—wood, drywall, fabric, and your skin. Over time, this causes wood floors and furniture to shrink and crack, drywall to become brittle, and paint to peel. Your eyes, nose, and throat will feel irritated, and you may experience more static electricity shocks and increased respiratory discomfort, especially if you have asthma or allergies.
The energy cost is also unnecessary. A dehumidifier uses 300 to 700 watts depending on the model, and running it continuously through winter adds to your heating bill without solving any real problem. If you notice static electricity, dry skin, or cracked wood in winter, the solution is to add moisture back into the air with a humidifier, not remove more with a dehumidifier.
Basements and crawlspaces are the main winter exception
Basements and crawlspaces are colder than the rest of the house and often stay damp year-round because they are partially underground and exposed to soil moisture. Even in winter, these spaces may reach 50 to 60 percent humidity or higher, especially if there is poor drainage or a water intrusion problem. In these cases, running a dehumidifier in the basement or crawlspace alone—not in the living areas above—can prevent mold growth and musty odors.
The key is to treat the basement as a separate zone. Close the door to the basement, run the dehumidifier there, and let the rest of the house maintain its natural winter humidity. This way you are only dehumidifying the space that actually needs it. If your basement stays dry in winter, you do not need the dehumidifier running at all. Check the humidity with an inexpensive digital hygrometer (around $10 to $20) before deciding to run it.
Warm climates where winter humidity stays high
If you live in a warm, humid region—southern Florida, coastal Louisiana, parts of southern Texas, or Hawaii—winter temperatures may stay above 60°F, and outdoor humidity may remain high even when it is cooler. In these climates, indoor humidity can stay above 50 percent year-round, even in winter, because the air outside is still moisture-rich and your air conditioning may not run as often to remove that moisture.
In these cases, you may need to run a dehumidifier throughout the year, including winter. The best way to know is to measure your indoor humidity with a hygrometer. If it consistently stays above 50 percent in winter, mold and dust mites can thrive, and a dehumidifier is worth running. If it drops below 40 percent, turn it off. The climate and your specific home are what matter, not the calendar.
Signs your home is too dry in winter
If you are experiencing any of these symptoms in winter, your home is too dry and you should not run a dehumidifier:
- Dry, itchy skin and lips that do not improve with lotion
- Frequent nosebleeds or a constantly dry nose
- Cracked wood in floors, furniture, or trim
- Paint peeling or wallpaper lifting at the edges
- Frequent static electricity shocks
- Increased coughing or throat irritation, especially at night
All of these point to humidity that is too low, usually between 15 and 30 percent. The fix is to run a humidifier, not a dehumidifier. A small tabletop humidifier in your bedroom or living room can raise humidity to a comfortable 40 to 50 percent without the energy cost of heating the whole house more.
How to store your dehumidifier for winter
Before storing your dehumidifier, empty the water tank or disconnect the drain hose, and wipe down the coils and interior with a dry cloth to prevent mold growth while it sits unused. Store it in a cool, dry place—a basement, garage, or closet works well. Do not store it in an unheated shed or garage where temperatures drop below freezing, because the refrigerant inside can thicken and damage the compressor.
When you take it out again in spring or early summer, let it sit at room temperature for a few hours before plugging it in. This allows any refrigerant that may have thickened during storage to return to its normal state. Check the filter or coils for dust and clean them if needed before running it again.
Frequently Asked Questions
Can low humidity in winter damage my house?
Yes, humidity below 25 percent for extended periods can cause wood to shrink and crack, drywall to become brittle, and paint to peel. However, this is a reason to add moisture with a humidifier, not to remove more with a dehumidifier. Winter humidity is naturally low, and you cannot fight that by dehumidifying further.
Should I run a dehumidifier in my basement in winter?
Only if your basement stays above 50 percent humidity in winter. Use a hygrometer to check. If it does, running a dehumidifier in the basement alone—with the door closed—can prevent mold. Do not run it in the living areas above, where humidity is already low.
What indoor humidity level is healthy in winter?
Between 30 and 50 percent is ideal for comfort and health. Below 25 percent causes dry skin and respiratory irritation. Above 60 percent encourages mold and dust mites. Winter naturally brings humidity to the lower end of this range, which is fine.
Does a dehumidifier help with heating costs?
No. A dehumidifier uses energy to remove moisture that is not a problem in winter. Running one will increase your electric bill without lowering your heating costs. If anything, it makes heating less efficient because very dry air feels colder than slightly humid air at the same temperature.
What if my home feels dry but a hygrometer shows 40 percent humidity?
Perception of dryness depends on temperature as well as humidity. A room at 68°F and 40 percent humidity may feel dry because the air is cool. Raising the temperature slightly or adding a small humidifier in the room you spend the most time in will feel more comfortable than running a dehumidifier, which will make it worse.