A dehumidifier will not lower the actual temperature, but it will make the room feel cooler
A dehumidifier removes moisture from the air, not heat. The thermometer in your room will stay the same or even rise slightly—dehumidifiers generate a small amount of heat as they run. But your body will feel cooler because dry air allows sweat to evaporate from your skin more easily. That evaporation is what creates the sensation of cooling, even though the room temperature itself has not changed.
This matters because comfort is not the same as temperature. You can feel cold in a 72-degree room if the air is saturated with moisture, and comfortable in a 75-degree room if the air is dry. A dehumidifier shifts you toward that second scenario by removing the moisture that traps heat against your skin.
Key Takeaways
- A dehumidifier makes a room feel cooler by letting sweat evaporate faster, but it does not lower the actual air temperature.
- The machine itself generates a small amount of heat as it runs, so the room temperature may stay the same or rise slightly.
- Humidity above 50 percent makes heat feel worse; bringing it down to 30–50 percent noticeably improves comfort.
- If you need the room temperature to actually drop, you need an air conditioner, which cools and dehumidifies at the same time.
- Running a dehumidifier and an air conditioner together wastes energy because the AC is already removing humidity.
Why humidity makes heat feel worse
Your body cools itself by sweating. When sweat evaporates from your skin, it pulls heat away and you feel cooler. But if the air is already saturated with moisture, sweat cannot evaporate—it just sits on your skin. The result is that you feel hotter and more uncomfortable, even though the actual temperature has not changed.
This is why a humid 78-degree day feels worse than a dry 85-degree day. Meteorologists measure this with something called the heat index, which combines temperature and humidity to show what the air actually feels like. At 78 degrees and 90 percent humidity, the heat index is around 88 degrees. At 85 degrees and 30 percent humidity, it feels like 84 degrees. The second scenario is more comfortable even though it is hotter on the thermometer.
A dehumidifier solves the evaporation problem by pulling moisture out of the air. Once the humidity drops, sweat evaporates again, and your body's natural cooling system works the way it is supposed to.
How much cooler will it feel
The difference depends on how humid the room is to start with. If your room is at 80 percent humidity and you bring it down to 50 percent, the improvement in comfort will be noticeable—many people describe it as feeling 3 to 5 degrees cooler. If the room is already at 50 percent humidity, running a dehumidifier will make almost no difference in how you feel.
Most people feel comfortable between 30 and 50 percent relative humidity. Below 30 percent, the air feels dry and can irritate your skin and sinuses. Above 50 percent, moisture starts to trap heat against your body and mold and dust mites become more likely to grow. A dehumidifier's job is to keep you in that comfortable middle range.
The heat a dehumidifier actually produces
A dehumidifier removes water from the air by running it over cold coils, then warming that air back up before releasing it into the room. This warming step means the machine puts a small amount of heat back into the space—usually between 5 and 15 percent of the energy it uses. In a small, sealed room, this can raise the temperature by 1 to 2 degrees.
This is why a dehumidifier alone is not a good solution if your goal is to lower the actual temperature. The machine will make the room feel more comfortable by drying the air, but the thermometer may not move, or may even go up slightly. If you need the temperature to actually drop, you need cooling equipment, not just dehumidification.
Dehumidifiers versus air conditioners
An air conditioner does two things at once: it lowers the temperature and removes humidity. It works by running air over cold coils (the same way a dehumidifier does), but instead of warming that air back up and releasing it into the room, it sends the cold air directly into the space. The result is that the room gets both cooler and drier.
Because an air conditioner already removes humidity, running a dehumidifier at the same time wastes energy. The AC is doing the dehumidification job, and the dehumidifier is just adding heat to a space that the AC is trying to cool down. If you have central air or a window unit, you do not need a separate dehumidifier unless the AC is not keeping up with the moisture—which usually means the AC is undersized for the space or not running long enough.
A dehumidifier makes sense in situations where you cannot run an air conditioner: a basement that stays cool naturally but gets damp, a room in a humid climate where you do not want to cool the whole house, or a space where you need to control moisture without lowering the temperature.
When a dehumidifier is the right choice
Use a dehumidifier if the room is cool enough but too humid. Basements are the classic example—they stay naturally cool but often feel clammy because moisture seeps in from the ground. A dehumidifier will make the space feel more comfortable without wasting energy on cooling air that is already the temperature you want.
A dehumidifier also works well in humid climates where you want to reduce moisture without running the air conditioner constantly. If you live somewhere with high humidity but moderate temperatures, a dehumidifier can improve comfort and reduce mold risk while keeping your energy bill lower than running AC would.
In summer, if your air conditioner is running and the room still feels clammy, the problem is usually that the AC is not sized correctly for the space or is not running long enough to remove all the moisture. Adding a dehumidifier will not solve this—you need to fix the AC system itself. Call an HVAC technician to check whether the unit is the right size and whether the refrigerant charge is correct.
How to measure humidity in your room
You can buy an inexpensive hygrometer—a device that measures relative humidity—at any hardware store or online for $10 to $30. Digital models are more accurate than dial types. Place it in the room where you spend the most time, away from direct sunlight and away from doors or windows where air moves around.
Check the reading over a few days to get a sense of the pattern. Humidity is usually highest in the morning and lowest in the afternoon. If the reading consistently stays above 50 percent, a dehumidifier may improve comfort. If it is below 50 percent, a dehumidifier will not make much difference in how the room feels.
Frequently Asked Questions
Can I use a dehumidifier instead of an air conditioner to cool my room?
No. A dehumidifier will make the room feel more comfortable by removing moisture, but it will not lower the temperature. If you need the room to actually be cooler, you need an air conditioner or a window unit. A dehumidifier is useful only when the temperature is already acceptable but the air is too humid.
Will a dehumidifier help if my air conditioner is running?
Not usually. An air conditioner already removes humidity as it cools. If the room still feels damp while the AC is running, the problem is that the unit is undersized or not running long enough. A dehumidifier will not fix this—you need an HVAC technician to check the system.
Does a dehumidifier use a lot of electricity?
A typical dehumidifier uses 300 to 700 watts, depending on size and how hard it is working. Running one continuously costs roughly $10 to $25 per month in electricity, though this varies by your local rates. An air conditioner uses more energy, so if you can use a dehumidifier instead, you will save money.
What humidity level should I aim for?
Most people feel comfortable between 30 and 50 percent relative humidity. Below 30 percent, the air feels dry and can irritate skin and sinuses. Above 50 percent, moisture starts to trap heat and create conditions where mold and dust mites thrive. Use a hygrometer to check your room and adjust the dehumidifier to stay in that range.
Can I leave a dehumidifier running all the time?
Yes, but you do not need to. Most dehumidifiers have a humidistat that turns the machine off once the humidity drops to your target level, then turns it back on if humidity rises again. This automatic cycling saves energy and prevents the air from becoming too dry. Check your model's manual for the recommended settings.