A room gets warmer when the dehumidifier is on because the device uses electricity, and that electricity eventually ends up as heat in the room. With many dehumidifiers, heat is also released when water vapor condenses into liquid. The effect is usually small, but you can notice it in a small, enclosed space.
Direct answer: the heat comes from the device's electricity consumption and, in many models, from the heat released during condensation. The temperature difference is usually limited.
Where does the heat come from?
Every watt an electrical device uses eventually ends up as heat in the room. A dehumidifier with a power consumption of 80 watts, such as the Dynter DH251, therefore gives off about as much heat as an old incandescent light bulb of the same wattage. That is not much, but it does make a difference in a small room without ventilation.
Condensation also plays a role. Water in the air contains energy. When water vapor is converted into liquid, that energy is released as heat. This happens with dehumidifiers that work by passing air over a cold surface. Exactly how much extra heat is released depends on the type of device and the amount of moisture removed from the air.
Why does the air feel warmer but also drier?
Warm air can contain more moisture than cold air. When the air is made drier by the device, it often feels different than you would expect based on the temperature. You can read about how moisture and perceived temperature are related in how humidity affects perceived temperature.
How much warmer does it get?
This varies depending on the situation. The outcome depends on the size of the room, the ventilation, the insulation, and how long the device runs. The table below shows the most important factors.
| Factor | Effect on heat |
|---|---|
| Small, enclosed room | Heat lingers, effect more noticeable |
| Large or ventilated space | Heat dissipates faster, effect barely noticeable |
| Running for a long time consecutively | More accumulated heat |
| A lot of moisture in the air | More condensation, so more released heat |
What can you do about it?
If the extra heat is bothersome, for example in a bedroom in summer, then do not use the dehumidifier in an enclosed space without air circulation. It is best to run it during the day or at a time when you are not in the room. Also make sure there is enough free space around the device; you can find out exactly how much in where to place a dehumidifier. If you want to know how long it needs to run per day, see how long a dehumidifier needs to run per day.
Use the timer function to turn the device off automatically. If you want to keep track of the electricity consumption, read how much electricity a dehumidifier uses per day.
Dynter DH251 dehumidifier
The Dynter AirPure DH251 dehumidifier is intended for spaces up to 55 m².
Dehumidification: up to 900 ml per day
Water tank: 3800 ml
Power: 80 W
Timer: adjustable from 1 to 24 hours
Night mode: display off for a peaceful sleep
Safety: safety sensor that switches off when the tank is full
Dimensions and weight: 24 x 13.4 x 37 cm, 2.51 kg
You can find more options in the Dynter dehumidifier collection.
Frequently asked questions
Is it normal for my dehumidifier to feel warm?
Yes, that is normal. Electrical devices give off heat, and dehumidifiers often also release heat from condensation.
Does a dehumidifier heat the room enough to replace a heater?
No. The heat is a byproduct; the device is not designed to heat a room.
Can I leave a dehumidifier running overnight?
Yes, you can. For more information, read can a dehumidifier stay on overnight.
Why does the air feel warm at the outlet?
The air flows past components of the device that give off heat, which can make the blown air feel warmer than the surrounding air.