A dehumidifier does not lower the air temperature, but it can make a room feel cooler
A dehumidifier removes moisture from the air, not heat. The temperature reading on a thermometer will stay the same or even rise slightly—the machine generates a small amount of heat as it runs. What changes is how the air feels on your skin. When humidity drops, sweat evaporates faster from your body, and that evaporation creates the sensation of coolness. In a humid 78°F room, you might feel uncomfortable; in a dry 78°F room, you feel noticeably better.
This is an important distinction because it shapes what a dehumidifier can and cannot do for you. If your goal is to lower the actual temperature in a room, a dehumidifier will not accomplish that—you need an air conditioner. If your goal is to feel more comfortable and reduce moisture damage to your home, a dehumidifier works well and costs far less to run than cooling equipment.
Key Takeaways
- A dehumidifier removes water from the air but does not reduce temperature; the room may feel slightly warmer because the machine produces heat as it operates.
- Lower humidity makes sweat evaporate faster from your skin, creating the sensation of coolness even though the actual air temperature has not changed.
- Dehumidifiers work best in spaces where humidity is the main comfort problem—basements, bathrooms, and naturally damp climates—rather than in hot, dry environments.
- Running a dehumidifier costs significantly less than running an air conditioner, but it will not replace air conditioning in genuinely hot conditions.
How humidity affects what temperature feels like
Your body cools itself by sweating and then evaporating that sweat through the skin. When the air is already saturated with moisture—high humidity—sweat cannot evaporate as easily. The sweat stays on your skin, and your body stays hot. When humidity is low, sweat evaporates quickly, and your body sheds heat efficiently. This is why 75°F at 30% humidity feels pleasant, while 75°F at 80% humidity feels sticky and oppressive.
A dehumidifier lowers the humidity level in a room by pulling moisture out of the air and collecting it in a tank or draining it away. As humidity drops, your sweat evaporates faster, and you feel cooler—even though the thermometer reads the same temperature it did before. This effect is real and measurable in terms of comfort, but it is not the same as lowering the actual temperature.
Why a dehumidifier may feel like it is warming the room slightly
Dehumidifiers use energy to pull moisture from the air, and that process generates heat. The compressor, motor, and other internal components all produce warmth as they work. In a small, enclosed space, this heat output can raise the room temperature by 1 to 3 degrees Fahrenheit, depending on the machine's size and how long it runs. This is a real effect, not a perception.
In practice, this small temperature increase is usually outweighed by the comfort gain from lower humidity. A room that becomes 1 degree warmer but 20 percentage points drier often feels significantly more comfortable overall. However, if the room is already hot and you are hoping to cool it down, adding a dehumidifier will make the actual temperature situation slightly worse, even if the humidity drop makes you feel better.
When a dehumidifier actually helps with comfort
Dehumidifiers work best in humid climates or in specific rooms where moisture is trapped. Basements, bathrooms, laundry rooms, and kitchens are common places where humidity builds up faster than it can escape. In these spaces, a dehumidifier can drop humidity from 70% or 80% down to a comfortable 40% to 50%, and that shift makes a real difference in how the room feels and smells.
Dehumidifiers also prevent the damage that high humidity causes: mold growth, musty odors, warped wood, and rust on metal. If you live in a naturally damp climate—near the coast, in a swampy region, or in a basement apartment—a dehumidifier protects your belongings and health while also improving comfort. In these situations, the machine is solving a real problem, not just chasing a temperature number.
Dehumidifiers versus air conditioners: what each one does
An air conditioner removes both heat and moisture from the air. It cools the room down and also lowers humidity as a side effect. A dehumidifier removes only moisture; it does not cool. If your space is genuinely hot—above 80°F—and you want it cooler, an air conditioner is the tool you need. If your space is warm and humid, and you want to feel more comfortable without lowering the temperature, a dehumidifier may be enough.
Air conditioners cost more to buy and significantly more to run than dehumidifiers. A typical window air conditioner uses 500 to 1500 watts per hour, while a dehumidifier uses 300 to 700 watts. If you are trying to reduce energy costs, a dehumidifier is the cheaper option—but only if humidity, not heat, is your main problem. Using a dehumidifier to avoid running an air conditioner in a genuinely hot room will leave you uncomfortable and will not save money in the long run.
How to tell if a dehumidifier will help your situation
Check the humidity level in your room with an inexpensive hygrometer, a small device that measures moisture in the air. You can buy one at any hardware store for $10 to $30. If humidity is above 60%, a dehumidifier will likely improve comfort and prevent moisture damage. If humidity is below 50%, the air is already dry, and a dehumidifier will not help—it may even make the air uncomfortably dry.
Also consider the actual temperature. If the room is 72°F and humid, a dehumidifier is a good choice. If the room is 85°F and humid, you need cooling, not just dehumidification. A dehumidifier alone will not solve the problem, and it will add a small amount of heat to an already hot space. In that case, an air conditioner or a combination of air conditioning and dehumidification is the right approach.
Tips for using a dehumidifier effectively
Place the dehumidifier in the center of the room or in the area where humidity is highest, not in a corner or against a wall. The machine pulls in humid air from one side and releases drier air from the other, so it needs space to work. Close doors and windows to keep the humid outside air from entering while the machine runs. If you are dehumidifying a basement or bathroom, close the door to that room so the machine does not waste energy trying to dry the entire house.
Empty the collection tank regularly, or set up a drain hose if your model supports it. A full tank will shut the machine off automatically on most models, so you will not get continuous operation. Run the dehumidifier during the day when humidity tends to be highest, and turn it off at night if humidity has dropped to your target level. Check the humidity with a hygrometer every few days to see if the machine is working and to avoid over-drying the air, which can cause dry skin, static electricity, and damage to wood furniture.
Frequently Asked Questions
Will a dehumidifier cool down my bedroom at night?
No, it will not lower the temperature. It will make the room feel slightly more comfortable by allowing sweat to evaporate faster, but the thermometer will read the same or slightly higher. If the room is hot, you need an air conditioner or a fan to cool it down.
Can I use a dehumidifier instead of air conditioning to save money?
Only if humidity is your main problem, not heat. In a humid but moderately warm room, a dehumidifier uses less energy than an air conditioner and may be enough. In a genuinely hot room, a dehumidifier will not cool you down, and you will end up running both the dehumidifier and a fan or air conditioner anyway, which costs more than just using air conditioning alone.
Does a dehumidifier make a room drier or cooler?
A dehumidifier makes a room drier by removing moisture from the air. The drier air allows your body to cool itself more efficiently through sweat evaporation, so you feel cooler—but the actual air temperature stays the same or rises slightly.
What humidity level should I aim for with a dehumidifier?
Most experts recommend keeping indoor humidity between 30% and 50%. Below 30% is too dry and can irritate your skin and respiratory system. Above 60% encourages mold growth and dust mites. Use a hygrometer to monitor levels and adjust the dehumidifier as needed.
Is it normal for a dehumidifier to feel warm?
Yes. The machine generates heat as it operates, so the air coming out of it is warmer than the air going in. This is why a dehumidifier may raise the room temperature by 1 to 3 degrees. This is normal and does not mean the machine is broken.