Yes, dehumidifiers raise room temperature, but the effect is usually small
A dehumidifier will make your room warmer — typically by 1 to 3 degrees Fahrenheit. This happens because the machine pulls moisture from the air and releases heat as a byproduct of that process. The warmer air comes from the compressor and condenser coils inside the unit, which generate heat while they work. If your room is already warm and humid, you will notice the temperature climb within 15 to 30 minutes of turning the dehumidifier on.
The amount of warming depends on three things: how large the dehumidifier is, how humid the room is when you start, and how well the room is sealed. A small portable unit in a large, open space will raise the temperature less noticeably than a large unit in a small bedroom. A very humid room (above 70 percent relative humidity) will see more warming than one that is already moderately dry, because the dehumidifier has to work harder and produce more heat.
This warming effect is not a bug — it is how the machine works. If you are running a dehumidifier to reduce moisture, you are also accepting that the room will get warmer. Some people use this to their advantage in damp basements or bathrooms where a little extra warmth is welcome. Others find it annoying and run the air conditioner at the same time to offset the temperature gain.
Key Takeaways
- Dehumidifiers raise room temperature by 1 to 3 degrees Fahrenheit because the compressor and condenser coils release heat while removing moisture.
- Larger units and more humid rooms produce more noticeable warming than smaller units or drier spaces.
- Running a dehumidifier and an air conditioner together will increase your energy bill but keeps humidity and temperature both under control.
- The warming effect is strongest in sealed rooms and weakest in spaces with good air circulation or open doors.
- If temperature control matters more than humidity reduction, a dehumidifier may not be the right tool for your situation.
How the heat gets released during dehumidification
A dehumidifier works by pulling warm, humid air over cold evaporator coils. The moisture condenses on those coils and drips into a tank or drain line. The air that comes back out of the machine is both drier and warmer than it went in. That warmth comes from the compressor, which is the engine of the whole system — it runs constantly while the machine is on, and compressors generate heat the same way a car engine does.
The condenser coils then release that heat into the room air before it exits the machine. So the room gets a double dose of warmth: first from the compressor itself, and second from the condenser coils that are designed to shed heat. In a small, sealed room, this heat has nowhere to go, so the temperature climbs steadily. In a room with open windows or doors, or in a large space where air can circulate freely, the warming is less obvious because the heat disperses.
This is why dehumidifiers are less efficient in very large spaces or in rooms that are not well sealed. The machine is working hard to remove moisture, but the heat it produces gets diluted across a bigger volume of air, and some of it may escape through gaps around doors and windows.
When the temperature rise matters most
In a basement or crawlspace, a 2-degree temperature increase is often not a problem and may even be helpful. Basements are typically cool and damp, and a dehumidifier running there will make the space feel more comfortable overall — less clammy, even if slightly warmer. The same is true in a bathroom after a shower, where removing moisture is the priority and a little extra warmth is a bonus.
In a bedroom or living room during summer, the temperature rise can be annoying. If your room is already 78 degrees and humid, a dehumidifier will push it to 80 or 81 degrees while drying out the air. You may feel more comfortable because dry air feels cooler than humid air at the same temperature, but the thermometer will show a real increase. If you are sensitive to heat or trying to keep cooling costs down, this trade-off matters.
In winter, a dehumidifier's heat output is usually welcome. Many people run dehumidifiers in basements or bedrooms during cold months to prevent mold and mildew, and the extra warmth reduces the load on the heating system slightly. The effect is small — you will not see a meaningful drop in your heating bill — but it works in your favor rather than against it.
Dehumidifiers versus air conditioners for temperature and humidity control
An air conditioner removes both moisture and heat, so it solves both problems at once. Running an air conditioner will lower the room temperature and reduce humidity simultaneously. A dehumidifier removes moisture but raises temperature, so it solves only half the problem. If you need to lower both temperature and humidity, an air conditioner is the more efficient choice.
However, air conditioners are more expensive to run than dehumidifiers, and they require a window unit or a central system. A portable dehumidifier costs less to operate and works in any room. So the choice depends on what you are trying to achieve. If humidity is the main problem and a small temperature increase is acceptable, a dehumidifier alone makes sense. If you need to cool the room and dry it out, an air conditioner is better.
Some people run both: a dehumidifier to handle moisture and an air conditioner to handle heat. This is the most expensive option but gives you independent control over each factor. You can set the air conditioner to a comfortable temperature and let the dehumidifier manage humidity without worrying about the warming effect.
How room size and sealing affect the temperature rise
A small, sealed bedroom will warm up faster and more noticeably than a large, open living room with the same dehumidifier running. In a 100-square-foot bedroom with the door closed, you might see a 3-degree rise within 30 minutes. In a 400-square-foot living room with open doors to adjacent spaces, the same machine might raise the temperature by only 0.5 degrees because the heat disperses into a larger volume of air.
Sealing matters because it traps the heat the dehumidifier produces. A room with weather stripping on the doors and windows, and no gaps around baseboards or vents, will hold onto that heat. A room with loose-fitting doors, window gaps, or open vents will let some of it escape. If you want to minimize the temperature rise, opening a window or door slightly will help, but then you are also letting humid air back in, which defeats part of the purpose.
The size of the dehumidifier also matters. A large unit rated for 70 pints per day will produce more heat than a small unit rated for 30 pints per day. If you are choosing a dehumidifier for a small space and temperature is a concern, a smaller unit will warm the room less, though it may take longer to reach your target humidity level.
Energy cost of running a dehumidifier versus the heating benefit
A typical portable dehumidifier uses 300 to 700 watts of electricity, depending on size and how hard it is working. Running one for 8 hours a day costs roughly $0.30 to $0.70 per day in electricity, or about $9 to $21 per month. The heat it produces might reduce your heating bill by a few dollars per month in winter, but that savings is small compared to the cost of running the machine.
In summer, the dehumidifier's heat is a liability, not a benefit. If you are running an air conditioner to cool the room, the dehumidifier's extra warmth forces the air conditioner to work harder and longer, which increases your cooling bill. Running both machines together costs more than running either one alone. The only reason to do it is if you need independent control — for example, if your air conditioner does not remove humidity well enough on its own.
The real cost of a dehumidifier is the electricity it uses, not the heat it produces. The warming effect is a side effect, not a feature you are paying for. If you are considering a dehumidifier mainly for the heat it generates, a space heater or your central heating system will do the job more efficiently.
Frequently Asked Questions
Will a dehumidifier keep my basement warm in winter?
A dehumidifier will raise the temperature slightly, but not enough to heat a basement on its own. The warming effect is typically 1 to 3 degrees, which is useful for preventing condensation and mold but not for maintaining comfort. If you need to heat a basement, use a space heater or extend your central heating system. A dehumidifier is a tool for moisture control, not heating.
Should I run my dehumidifier and air conditioner at the same time?
Only if your air conditioner is not removing humidity well enough. Most air conditioners handle both cooling and dehumidification, so running both machines wastes energy. If your room stays humid even with the air conditioner on, check the air conditioner's settings or have it serviced before adding a dehumidifier. Running both together will increase your energy bill noticeably.
Why does the air feel warmer when I turn on my dehumidifier?
The air is actually warmer — the thermometer will confirm it. The dehumidifier's compressor and condenser coils release heat as they remove moisture. You may also feel more comfortable because dry air feels cooler than humid air at the same temperature, even though the actual temperature has risen. Both effects are real.
Can I reduce the temperature rise by running my dehumidifier less often?
Yes, running the dehumidifier for shorter periods or on a lower setting will produce less heat. However, it will also remove moisture more slowly, so you will need to run it longer overall to reach your target humidity level. The total heat produced will be roughly the same. If temperature is a concern, consider whether a dehumidifier is the right tool for your situation.
Does a dehumidifier warm up faster than a space heater?
A dehumidifier is not designed to heat a room and will warm it much more slowly than a space heater. A 1500-watt space heater can raise a small room's temperature by 10 to 15 degrees in an hour. A dehumidifier using 500 watts will raise it by 1 to 3 degrees in the same time. If you need heat, use a heater. If you need to remove moisture, use a dehumidifier.