A dehumidifier will not cool your room, but it may feel cooler

A dehumidifier removes moisture from the air, not heat. The machine pulls humid air through a cold coil, water condenses out, and the dried air returns to your room at roughly the same temperature it entered—or sometimes slightly warmer, because the dehumidifier's motor generates a small amount of heat.

However, a dehumidifier can make a room feel cooler. Humid air holds heat and makes your skin feel sticky and uncomfortable. When moisture drops, your body can cool itself more efficiently through perspiration, so the room feels more pleasant even though the actual temperature has not changed. This is why 72°F at 30% humidity feels cooler than 72°F at 70% humidity.

If you are looking to lower the actual temperature, a dehumidifier alone will not do it. You need air conditioning, a window unit, or a portable AC machine. A dehumidifier is a tool for comfort and moisture control, not temperature control.

Key Takeaways

  • Dehumidifiers remove water from the air but do not lower room temperature; they may even raise it slightly because of heat from the motor.
  • Lower humidity makes a room feel cooler to your body because sweat evaporates more easily, even if the thermometer reads the same.
  • If you need to lower actual temperature, you need air conditioning or a portable AC unit, not a dehumidifier.
  • A dehumidifier works best in rooms that are already cool but too humid—basements, bathrooms after showers, or bedrooms in damp climates.
  • Running a dehumidifier and an air conditioner together can reduce the AC's workload and lower your energy costs.

How a dehumidifier actually works

A dehumidifier pulls humid air across a cold evaporator coil. As the warm, moist air touches the cold surface, water condenses into droplets—the same way water beads on a cold glass of iced tea. The water drips into a tank or drain line, and the now-dried air passes over a warm condenser coil before returning to the room.

That condenser coil is where heat enters the equation. The coil warms the air slightly as it releases the heat that was removed from the evaporator. The result: the air leaving the machine is roughly the same temperature as when it entered, or a degree or two warmer. The machine's compressor and motor also generate heat, which adds to the room's total warmth.

This is why running a dehumidifier in a closed room for hours can actually raise the room temperature by a few degrees. The machine is working hard, and that work produces heat as a byproduct.

Why humidity makes you feel hot

Your body cools itself by sweating and letting that sweat evaporate from your skin. In dry air, sweat evaporates quickly and efficiently, pulling heat away from your body. In humid air, sweat cannot evaporate as easily because the air is already saturated with moisture. The sweat sits on your skin, making you feel clammy and overheated, even if the temperature is moderate.

This is why a dehumidifier can improve comfort in a cool but damp room. By lowering humidity from 70% to 40%, you restore your body's ability to cool itself through perspiration. The room temperature stays the same, but you feel noticeably better.

The difference is real but limited. A dehumidifier cannot replace air conditioning in a hot room. It is a comfort tool for moisture problems, not a cooling tool for heat problems.

When a dehumidifier and air conditioner work together

If you have both a dehumidifier and air conditioning, running them together can actually save energy. An air conditioner cools and dehumidifies at the same time, but it has to work harder to remove moisture from very humid air. If you run a dehumidifier first to drop humidity, your AC does not have to work as hard to maintain the temperature you want.

This is most useful in climates where humidity is high but outdoor temperatures are mild—spring and fall, or in naturally damp regions. In summer heat, your AC is already running at full capacity, and adding a dehumidifier may not save energy because the dehumidifier itself uses power.

The practical approach: if your AC is keeping up with the heat but the air still feels clammy, a dehumidifier can help. If your AC is struggling to cool the room, the problem is heat, not humidity, and a dehumidifier will not solve it.

Rooms where a dehumidifier actually helps

Basements are the classic case. A basement stays cool naturally because it is below ground, but it often stays damp. A dehumidifier removes that moisture without raising the temperature, making the space more comfortable and protecting stored items from mold and mildew.

Bathrooms after a hot shower are another good use. The room is warm and steamy. A dehumidifier pulls moisture out of the air, reducing the risk of mold on walls and ceilings. It will not cool the room, but it will prevent the moisture from lingering for hours.

Bedrooms in humid climates—coastal areas, the Southeast, or anywhere with high summer humidity—benefit from a dehumidifier running at night. The room stays cool from the AC or open windows, but the dehumidifier keeps the air from feeling sticky and improves sleep quality.

Portable AC units if you need actual cooling

If your goal is to lower room temperature, not just reduce humidity, you need a different tool. A portable air conditioner or window AC unit removes heat from the room and vents it outside. These machines actually cool, unlike dehumidifiers.

Portable AC units are more expensive than dehumidifiers and use more electricity, but they do the job a dehumidifier cannot. They also dehumidify as a side effect, so you get both benefits in one machine.

Window units are more efficient than portable models because they vent heat directly outside through the window. Portable units need a vent hose, which is less efficient but easier to install in a rental or temporary setup.

The energy cost of running a dehumidifier

A typical dehumidifier uses 300 to 700 watts, depending on size and how hard it is working. Running one continuously costs roughly $20 to $50 per month in electricity, depending on your local rates and how often it runs. A larger unit or one running in a very humid space will cost more.

This is less than a portable AC unit, which uses 1,000 to 1,500 watts and costs $50 to $150 per month. But it is more than a ceiling fan, which uses 10 to 50 watts.

The cost is worth it if you have a genuine moisture problem—mold risk, musty smell, or discomfort from humidity. It is not worth it if you are hoping to cool a hot room; the energy cost will not solve the real problem.

Frequently Asked Questions

Can I use a dehumidifier instead of air conditioning?

No. A dehumidifier removes moisture but does not lower temperature. If your room is hot, a dehumidifier will not cool it. If your room is already cool but feels clammy, a dehumidifier will help. For heat, you need air conditioning or a portable AC unit.

Will a dehumidifier make my room feel cooler?

Yes, it may feel cooler because lower humidity lets your body cool itself more efficiently through sweat evaporation. The actual temperature does not change, but comfort improves. This effect is strongest in already-cool rooms with high humidity.

Does a dehumidifier raise room temperature?

Slightly. The motor and compressor generate heat, and the condenser coil warms the air before it returns to the room. In a closed space running for hours, a dehumidifier can raise temperature by a few degrees. This is usually not noticeable but can matter in a small, sealed room.

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

It depends. If your AC is keeping up with cooling but the air feels humid, a dehumidifier can improve comfort and may reduce the AC's workload slightly. If your AC is already struggling to cool the room, adding a dehumidifier will not help and will only use more electricity.

What is the difference between a dehumidifier and a portable air conditioner?

A dehumidifier removes moisture; a portable AC removes heat. A portable AC also dehumidifies as a side effect. If you need to lower temperature, a portable AC is the right tool. If you need to remove moisture from an already-cool room, a dehumidifier is cheaper and uses less power.