Does a Dehumidifier Actually Cool Down a Room?

A dehumidifier removes moisture but does not lower air temperature

A dehumidifier will not make your room cooler in the way an air conditioner does. The machine pulls water vapor out of the air, which can make the space feel slightly more comfortable, but the actual temperature stays the same or may even rise slightly. The motor and compressor inside a dehumidifier generate heat as they run, so in a small, sealed room, the air temperature can actually go up by a degree or two.

What you might notice instead is a change in how the air feels on your skin. Humid air holds heat differently than dry air, so removing moisture can create the sensation of coolness even though a thermometer would show no real temperature drop. This is why people often say a dehumidifier makes a room feel more comfortable — it does, but through humidity control, not cooling.

Key Takeaways

A dehumidifier removes water from the air but does not lower the room temperature; the air may actually warm slightly because the machine produces heat.
Humid air feels warmer than dry air at the same temperature, so removing moisture can make a room feel more pleasant without changing the thermometer reading.
If you need actual cooling, an air conditioner or window unit is the right tool; a dehumidifier is for moisture control in already-cool spaces.
Running a dehumidifier in a very small, sealed room can raise the temperature enough to be noticeable, especially if the unit runs continuously.

Why humidity makes temperature feel different

Your body cools itself by sweating, and sweat evaporates from your skin to carry heat away. When the air is already full of moisture, sweat cannot evaporate as easily, so you feel hotter even if the actual temperature is moderate. A dehumidifier removes that moisture, allowing sweat to evaporate more freely, which is why the room feels more comfortable.

This is measured as relative humidity — the amount of water vapor in the air compared to how much the air can hold at that temperature. On a 72-degree day, 30 percent humidity feels cool and dry, while 80 percent humidity feels sticky and warm. A dehumidifier lowers that percentage, which changes how your body experiences the temperature, but the thermometer still reads 72 degrees.

The heat a dehumidifier actually produces

Every dehumidifier has a compressor and motor that consume electricity and generate heat as a byproduct. In a large room with good air circulation, this heat disperses and you do not notice it. In a small bedroom with the door closed, or in a basement where air does not move much, the warmth from the machine can raise the room temperature by one to three degrees over several hours of continuous operation.

This effect is most noticeable with larger, more powerful units. A small portable dehumidifier in a 200-square-foot room will have a smaller impact than a whole-home system running in a basement. If you are trying to cool a space, running a dehumidifier will work against you by adding heat, even as it removes moisture.

When a dehumidifier actually helps with comfort

A dehumidifier works best in spaces that are already cool enough but feel clammy or damp. Basements, bathrooms after a shower, and bedrooms in humid climates are common examples. The machine removes the moisture that makes these spaces feel uncomfortable, and the slight temperature increase from the motor is usually too small to matter in a larger area.

If your air conditioner is already running, a dehumidifier can improve comfort by letting the AC work more efficiently. When humidity is lower, the air conditioner does not have to work as hard to remove moisture, so it can focus on cooling. This combination — AC for temperature, dehumidifier for moisture — is common in very humid climates like the Southeast or in homes with poor ventilation.

Dehumidifier versus air conditioner: which tool to use

If your goal is to lower the room temperature, an air conditioner is the only tool that will do it. Window units, portable AC units, and central air all remove heat from the space and exhaust it outside. A dehumidifier cannot do this; it only removes water.

Choose a dehumidifier if the temperature is already acceptable but the air feels damp or sticky. Choose an air conditioner if the room is too warm. Some people use both — the AC cools the space, and the dehumidifier handles any remaining moisture that the AC does not remove. This is especially common in humid climates where even a running air conditioner leaves the air feeling clammy.

How to measure whether a dehumidifier is helping

The best way to know if a dehumidifier is working is to check the humidity level before and after. A hygrometer is an inexpensive tool (usually $15 to $40) that measures relative humidity. Most people feel comfortable between 30 and 50 percent humidity. If your space is above 60 percent, a dehumidifier will make a noticeable difference in comfort.

You can also pay attention to physical signs: condensation on windows, a musty smell, or damp spots on walls all indicate high humidity. If these improve after running a dehumidifier for a few days, the machine is doing its job. If the room still feels warm and sticky, the temperature itself may be the problem, and you need cooling, not dehumidification.

Room size and dehumidifier effectiveness

A dehumidifier's ability to remove moisture depends on the size of the space and the unit's capacity. Manufacturers rate dehumidifiers by how many pints of water they can remove per day — typically 30, 50, or 70 pints. A 30-pint unit works well for a small bedroom or bathroom, while a 70-pint unit is better for a basement or large living area.

Using an undersized dehumidifier in a large space means it will run constantly and may not keep up with moisture production. Using an oversized unit in a tiny room means it will cycle on and off frequently, which wastes energy. Matching the unit size to your room is important for both effectiveness and the amount of heat the machine adds to the space.

Frequently Asked Questions

Will a dehumidifier cool down a hot room?

No. A dehumidifier removes moisture but does not lower temperature. If anything, the heat from the motor may raise the room temperature slightly. For actual cooling, you need an air conditioner or window unit.

Can I use a dehumidifier instead of an air conditioner?

Not if your goal is to lower temperature. A dehumidifier only removes water from the air. However, if your room is already cool but feels damp, a dehumidifier will improve comfort without the cost of running an AC unit.

Does a dehumidifier use a lot of electricity?

A typical dehumidifier uses 300 to 700 watts, depending on size and how often it runs. This is less than an air conditioner (which uses 1,000 to 1,500 watts) but more than a fan. Running it continuously in a humid space will add to your electric bill, though usually not dramatically.

Why does my room feel cooler after I run a dehumidifier if the temperature does not change?

Humid air feels warmer because sweat cannot evaporate from your skin as easily. When a dehumidifier removes moisture, sweat evaporates faster, and your body feels cooler even though the thermometer reads the same. This is a real comfort improvement, just not an actual temperature drop.

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

Yes, in very humid climates. The AC cools the space and removes some moisture, while the dehumidifier handles any remaining dampness. This combination is common in the Southeast and other humid regions where AC alone does not bring humidity down to comfortable levels.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.