Do Dehumidifiers Actually Cool Down a Room?

Dehumidifiers Remove Moisture, Not Heat

No, dehumidifiers do not cool down a room. They remove water vapor from the air, which is a different job than lowering temperature. A dehumidifier pulls moisture out and exhausts it, but the air that comes back into your room is actually slightly warmer than when it entered the machine.

This happens because the dehumidifier uses energy to condense water vapor into liquid. That energy has to go somewhere, and most of it becomes heat. So while your air feels less sticky and more comfortable, the thermometer reading stays the same or goes up by a degree or two.

The confusion is understandable: humid air often feels hotter than dry air at the same temperature. Your body cools itself by sweating, and sweat only works when it can evaporate into the air. In high humidity, sweat stays on your skin instead of evaporating, so you feel hotter and more uncomfortable. A dehumidifier fixes that discomfort by making sweat evaporate faster—but it is not lowering the actual temperature.

Key Takeaways

• Dehumidifiers remove moisture from air but produce heat as a byproduct, so the room temperature stays the same or rises slightly.
• Humid air feels hotter than dry air because your body cannot cool itself through sweat evaporation when moisture is already in the air.
• A dehumidifier makes you feel more comfortable by letting sweat evaporate, even though the actual temperature has not changed.
• If you need to lower the actual temperature, you need air conditioning, not a dehumidifier.
• Running a dehumidifier and an air conditioner together uses more energy than either alone, because the AC has to cool the heat the dehumidifier produces.

Why Humid Air Feels Hot

Your skin cools itself through evaporation. When sweat evaporates, it pulls heat away from your body. But evaporation only happens when the air around you has room for more moisture. In a humid room, the air is already saturated with water vapor, so your sweat cannot evaporate—it just sits on your skin, making you feel sticky and overheated.

This is why a dehumidifier can make a room feel 3 to 5 degrees cooler even though the thermometer does not move. You are not actually cooler; your body is just able to cool itself again. The relief is real, but it is not the same as air conditioning.

The Heat a Dehumidifier Produces

Every dehumidifier generates heat as it works. The machine pulls air in, cools it to condense the water vapor, collects the liquid water, and then warms the dried air back up before sending it out. That warming step is where the heat comes from—it is the energy cost of removing the moisture.

In a small, well-sealed room, you might notice the temperature rise by 1 to 3 degrees Fahrenheit after running a dehumidifier for several hours. In a larger space or a room with good air circulation, the heat spreads out and the temperature change is barely noticeable. But the heat is always there.

This is why running a dehumidifier and an air conditioner at the same time is inefficient. The AC cools the air, the dehumidifier heats it back up, and the AC has to cool it again. You are paying for both machines to work against each other.

When to Use a Dehumidifier Instead of Air Conditioning

A dehumidifier makes sense when humidity is your main problem and temperature is already comfortable. This happens in spring and fall, or in basements and bathrooms where moisture collects but the space is not too warm. If your basement stays 68 degrees but feels clammy, a dehumidifier will make it feel pleasant without wasting energy on cooling.

Dehumidifiers also cost less to run than air conditioning. A typical unit uses 300 to 700 watts, while a window air conditioner uses 1,000 to 1,500 watts. If you only need to dry out the air, a dehumidifier is the cheaper choice.

However, if the room is both hot and humid, you need air conditioning. An air conditioner removes both heat and moisture, so it solves both problems at once. A dehumidifier alone will only make the humidity better while the heat stays.

How to Tell If You Need a Dehumidifier or Air Conditioning

Check the temperature and humidity level in the room. If the temperature is comfortable (between 68 and 75 degrees) but the air feels sticky, a dehumidifier will help. If the temperature is above 75 degrees, you need air conditioning, whether or not the humidity is high.

You can measure humidity with an inexpensive hygrometer, which you can find at hardware stores for $10 to $30. Humidity above 60 percent starts to feel uncomfortable for most people. Above 70 percent, mold and dust mites thrive. A dehumidifier works best when humidity is between 60 and 75 percent and temperature is already acceptable.

If humidity is above 75 percent and temperature is also high, air conditioning is the right tool. If humidity is high but temperature is low (like in a damp basement in winter), a dehumidifier alone is enough.

Running a Dehumidifier Efficiently

Close doors and windows to keep the humid air from outside from entering. A dehumidifier works best in a sealed space where it can actually lower the moisture level instead of fighting a constant supply of wet air from outside.

Place the dehumidifier away from walls and furniture so air can flow freely around it. The machine pulls air in from one side and pushes it out the other, so blocking either side makes it work harder and produce more heat.

Empty the water tank regularly, or connect a drain hose if your model has one. A full tank will shut the machine off automatically on most models, so it stops working until you empty it. A drain hose lets it run continuously without your attention.

Run the dehumidifier during the day when you are home and can monitor it. At night, close the door to the room so the heat it produces does not spread through the house while you are sleeping.

Dehumidifiers and Energy Bills

A dehumidifier running 24 hours a day uses roughly 7 to 17 kilowatt-hours per month, depending on the model and how hard it has to work. At an average electricity rate of $0.14 per kilowatt-hour, that is $1 to $2.40 per month. Running it only during the day or only when humidity is high will cut that cost in half.

Air conditioning costs much more. A window unit running 24 hours uses 30 to 45 kilowatt-hours per month, or $4 to $6.30 at the same rate. Central air conditioning costs even more. So if you can solve the problem with a dehumidifier, your bill will be noticeably lower.

Frequently Asked Questions

Will a dehumidifier make my room feel cooler even if it does not lower the temperature?

Yes. Because dry air lets your sweat evaporate, your body can cool itself more effectively. You will feel 3 to 5 degrees cooler even though the thermometer does not change. This comfort is real, but it is not the same as actual cooling.

Can I use a dehumidifier instead of air conditioning in summer?

Only if the room is not too hot. If the temperature is already above 75 degrees, a dehumidifier will not help enough. You need air conditioning to remove heat. A dehumidifier works in summer only in naturally cool spaces that are also humid.

Should I run my dehumidifier and air conditioner at the same time?

No. Air conditioning already removes moisture, so running a dehumidifier alongside it wastes energy. The dehumidifier produces heat that the air conditioner has to cool again. Use one or the other, not both.

Does a dehumidifier use a lot of electricity?

A dehumidifier uses much less electricity than air conditioning—roughly one-third to one-half as much. If humidity is your only problem, a dehumidifier is the cheaper choice. But if you need both cooling and drying, air conditioning does both jobs more efficiently than running two machines.

What humidity level should I aim for?

Between 30 and 50 percent is ideal for comfort and health. Below 30 percent, the air feels dry and can irritate your skin and sinuses. Above 60 percent, mold and dust mites start to thrive. Most dehumidifiers have a dial or digital setting to stop running once humidity reaches your target level.