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

A dehumidifier removes moisture from the air, not heat. The machine pulls humid air across cold coils, water condenses and drains away, and the dried air passes over a warm compressor before returning to the room. That warm air is slightly warmer than when it entered — typically 2 to 5 degrees Fahrenheit higher. So a dehumidifier actually raises room temperature while lowering humidity.

However, lower humidity feels cooler on your skin. Sweat evaporates faster in dry air, which is why 75 degrees at 30% humidity feels more comfortable than 75 degrees at 70% humidity. This sensation of comfort is real, but the thermometer will not move down. If your room is 78 degrees and you run a dehumidifier, it may reach 80 or 81 degrees while feeling less sticky.

If cooling the room is your goal, a dehumidifier is not the tool. An air conditioner removes both heat and moisture. A fan circulates air without changing its temperature. A dehumidifier does only one job: dry the air.

Key Takeaways

  • Dehumidifiers raise room temperature by 2 to 5 degrees while removing moisture, so the room gets warmer, not cooler.
  • Lower humidity makes the same temperature feel more comfortable because sweat evaporates faster, but this is a sensation, not an actual temperature drop.
  • If you need to lower room temperature, use an air conditioner or fan instead; a dehumidifier works best alongside cooling equipment.
  • Dehumidifiers are most useful in basements, bathrooms, and other damp spaces where moisture is the main problem, not heat.

Why dehumidifiers produce heat instead of cold

A dehumidifier works by compressing refrigerant gas, which gets very cold. Air passes over these cold coils, moisture condenses into water, and the dried air continues through the machine. Before that air leaves the unit, it passes over the hot compressor — the part that does the compression work. This is where the heat comes from.

The compressor has to release all the energy it used to compress the refrigerant. That energy becomes heat. In a window air conditioner, the hot side of the compressor faces outside, so heat leaves the building. In a dehumidifier, the hot side faces the room, so heat stays inside. The machine is not designed to move heat outdoors; it is designed to remove water.

This is not a flaw — it is how the machine works. Every dehumidifier operates this way. Larger units produce more heat because they move more air and compress more refrigerant. A 50-pint dehumidifier (which removes 50 pints of water per day) will warm a room more than a 30-pint model.

When humidity matters more than temperature

In some situations, running a dehumidifier makes sense even though it raises temperature. Basements often stay cool and damp — 65 degrees and 80% humidity. The dampness causes mold, musty smells, and damage to stored items. Running a dehumidifier will raise the temperature to 67 or 68 degrees, but it will drop humidity to 50%, which stops mold growth. The small temperature increase is worth the protection.

Bathrooms after a shower are another example. Steam makes the room feel hot and sticky. A dehumidifier will dry the air faster than opening a window, and the slight temperature rise is barely noticeable because the humidity drop makes it feel more comfortable overall.

Crawl spaces, attics, and laundry rooms also benefit from dehumidifiers even though they warm slightly. The priority in these spaces is preventing moisture damage, not keeping cool. If temperature is your main concern, a dehumidifier is the wrong choice.

How to actually cool a room

An air conditioner removes heat and moisture at the same time. Window units, portable units, and central systems all work the same way: they move heat outside the building. The room temperature drops, and humidity drops as a side effect. This is the opposite of a dehumidifier.

A fan does not lower temperature but makes air feel cooler by moving it across your skin. Fans use far less electricity than air conditioners and produce no heat. In mild climates or during cool parts of the day, a fan may be enough.

If you need both cooling and dehumidification, run an air conditioner first. Air conditioners already remove humidity as part of their normal operation. Adding a dehumidifier afterward is unnecessary and will only waste electricity and raise temperature further.

Dehumidifier size and heat output

Dehumidifier capacity is measured in pints per day — the amount of water it removes in 24 hours. A 30-pint unit removes 30 pints; a 50-pint unit removes 50 pints. Larger units have larger compressors and produce more heat.

A small 30-pint dehumidifier might raise room temperature by 2 degrees. A large 70-pint unit might raise it by 4 or 5 degrees. The bigger the machine, the more noticeable the warming. This is one reason to choose the smallest dehumidifier that will handle your moisture problem — it will do less damage to room temperature.

Running time also matters. A dehumidifier that runs 8 hours per day produces less total heat than one running 16 hours. If your basement only needs drying during humid months, running the machine part-time keeps temperature rise lower.

Combining a dehumidifier with cooling

In humid climates, an air conditioner alone may not remove moisture fast enough. Some people run both an air conditioner and a dehumidifier. The air conditioner cools and removes some moisture; the dehumidifier removes additional moisture. The dehumidifier's heat output is small compared to the air conditioner's cooling power, so the room stays cool overall.

This setup makes sense in basements or other spaces where an air conditioner is not practical. A basement might have a small portable air conditioner for cooling and a dehumidifier for extra moisture removal. The air conditioner handles temperature; the dehumidifier handles the humidity that the air conditioner misses.

Without an air conditioner, running a dehumidifier alone will not cool the room. It will only make it feel slightly more comfortable by lowering humidity while actually raising temperature.

Humidity levels and comfort

The Environmental Protection Agency recommends keeping indoor humidity between 30% and 50%. Below 30%, air feels dry and can irritate skin and sinuses. Above 50%, mold and dust mites thrive. Most people feel most comfortable around 40% to 45%.

At 40% humidity, a room at 75 degrees feels pleasant. At 70% humidity, the same 75 degrees feels hot and sticky. This is why lowering humidity can make a room feel cooler even though the temperature rises slightly. The comfort gain from lower humidity often outweighs the discomfort from a 2-degree temperature increase.

However, if the room is already warm — 80 degrees or higher — adding a dehumidifier will make it feel worse. The temperature rise pushes it even higher, and no amount of humidity reduction will make 82 degrees feel cool. In hot climates, cooling must come first.

Frequently Asked Questions

Will a dehumidifier help if my air conditioner is already running?

Only if the air conditioner is not removing enough moisture. Most air conditioners remove humidity as they cool, so a dehumidifier is usually unnecessary. If your space still feels damp after the air conditioner runs, a dehumidifier can help, but it will also raise temperature slightly. Test it for a few days to see if the comfort gain is worth the extra electricity cost.

Can I use a dehumidifier instead of an air conditioner to save money?

No. A dehumidifier uses less electricity than an air conditioner, but it does not cool — it warms the room. If you need the room cooler, a dehumidifier will not help. If you only need to reduce moisture in a cool space, a dehumidifier can work without air conditioning.

How much will a dehumidifier raise my room temperature?

Typically 2 to 5 degrees Fahrenheit, depending on the unit size and how long it runs. A 30-pint dehumidifier in a small room might raise temperature 2 degrees. A 70-pint unit in the same room could raise it 5 degrees. Larger rooms see smaller temperature increases because the heat spreads over more space.

Is it normal for a dehumidifier to feel warm?

Yes. The air coming out of a dehumidifier is always warmer than the air going in. This is how the machine works — it cools air to remove moisture, then the compressor heats it before it exits. Feeling warm air from the outlet is normal and does not mean the unit is broken.

Should I run a dehumidifier in summer?

Only if you are not using an air conditioner or if the air conditioner is not removing enough moisture. In summer, an air conditioner is more efficient because it cools and dehumidifies at the same time. A dehumidifier running in summer will raise temperature while the air conditioner tries to lower it, wasting electricity. Use the dehumidifier in spring and fall when humidity is high but cooling is not needed.