Yes, dehumidifiers raise the air temperature, but only slightly
Dehumidifiers do heat the air as a side effect of how they work. When a dehumidifier pulls moisture out of the air, it releases that energy back into the room as heat. The temperature rise is usually small—typically 2 to 5 degrees Fahrenheit—but it is real and measurable. This happens because removing water vapor requires energy, and that energy has to go somewhere. In a dehumidifier, it goes back into the room instead of being vented outside.
The amount of heating depends on how hard the dehumidifier is working. A unit running constantly in a very humid basement will produce more noticeable warmth than one running occasionally in a drier space. The larger and more powerful the dehumidifier, the more heat it typically generates. This is why people sometimes notice their dehumidifier feels warm to the touch or why a room with a running dehumidifier can feel slightly warmer than expected.
Key Takeaways
- Dehumidifiers raise room temperature by 2 to 5 degrees Fahrenheit as they remove moisture from the air.
- The heating effect comes from the energy released during the dehumidification process, which stays in the room rather than escaping outside.
- Larger units and those running continuously produce more noticeable heat than smaller or intermittent ones.
- This temperature rise is usually a minor side effect, but it matters if you are trying to cool a room or keep energy costs down.
How the heating happens inside a dehumidifier
A dehumidifier works by pulling humid air over cold coils. The moisture in the air condenses on those coils, just like water beads up on a cold bathroom mirror. That condensed water drips into a tank or drain line. But the air that passes over the cold coils gets cooled first, then warmed again as it passes over the warm compressor and motor before leaving the unit. The net result is that the air exits slightly warmer than it entered.
The compressor is the main source of heat. It works hard to cool the coils, and all that mechanical effort generates warmth as a byproduct. That heat has nowhere to go except back into the room. This is the same reason a refrigerator feels warm on the back—the cooling process itself produces heat that must be released somewhere. In a dehumidifier, the back or sides of the unit will feel warm or even hot while it is running.
Why the temperature rise matters in different rooms
In a basement or crawlspace, the slight warming from a dehumidifier is often welcome. These spaces tend to be cool and damp, so a 3-degree temperature increase barely registers. The dehumidifier is solving the moisture problem, and any warmth is a bonus.
In a bedroom or living room, the heating effect can work against you. If you are running a dehumidifier because humidity is high in summer, that extra heat makes your air conditioner work harder to cool the space back down. You end up using more energy overall—the dehumidifier adds heat, and the AC has to remove it. In this situation, you are paying twice to solve the same problem.
In a very small room or closet, even 2 to 5 degrees can feel noticeable. A dehumidifier running in a small bedroom might make the room feel stuffy or warm, especially at night when you are trying to sleep. Larger rooms distribute the heat more evenly, so the effect is less obvious.
Comparing dehumidifier types and their heating output
| Type | How It Works | Heat Output |
|---|---|---|
| Refrigerant (most common) | Uses a compressor and cold coils to condense moisture | Moderate to high; compressor generates noticeable heat |
| Desiccant | Uses a moisture-absorbing material and a heating element to dry air | High; the heating element is intentional and adds significant warmth |
| Whole-house (ducted) | Pulls air from throughout the home and vents heat outside | Low to room; heat is ducted away rather than released into living space |
Desiccant dehumidifiers produce the most heat because they use an electric heating element as part of their drying process. They are often used in very cold or very dry climates where a refrigerant unit would not work well. If you are concerned about heating, a desiccant model is the wrong choice.
Refrigerant models are the standard for most homes and produce moderate heat from the compressor. This is the type you will find in most hardware stores and online retailers.
Whole-house dehumidifiers that vent to the outside produce the least noticeable heating in the room because the heat exits with the humid air. However, they are more expensive to install and require ductwork.
Strategies to reduce the heating effect
If the warmth from your dehumidifier is a problem, you have several options. The simplest is to run the unit only when you need it—at night or during the most humid part of the day—rather than continuously. This limits the total heat output.
You can also position the dehumidifier away from your main living space. Running it in a basement, garage, or utility room keeps the heat away from where you spend time. If the dehumidifier has a drain hose, you can run it to a floor drain or outside, which also helps move the warm exhaust away from occupied rooms.
Pairing a dehumidifier with good ventilation helps too. Opening a window or running a fan moves the warm air out of the room instead of letting it accumulate. In summer, this might seem counterintuitive, but if your humidity problem is severe enough to need a dehumidifier, the moisture control usually outweighs the minor heating effect.
If you are in a climate where both cooling and dehumidifying matter, a whole-house system or a unit that vents outside will serve you better than a portable model, even though the upfront cost is higher.
When heating from a dehumidifier is actually useful
In cold, damp spaces like basements, crawlspaces, and garages, the heat from a dehumidifier is often a welcome side effect. These areas are naturally cool, and the extra warmth can help prevent condensation and mold growth more effectively than cooling would.
In winter, when you are heating your home anyway, a dehumidifier's warmth does not work against you the way it does in summer. The heat just adds to what your furnace is already producing, so the energy cost is less noticeable. Winter humidity problems are less common, but when they occur—such as in a poorly ventilated bathroom or laundry room—a dehumidifier's heat is not a drawback.
Frequently Asked Questions
Will a dehumidifier make my room uncomfortably hot?
Probably not. A 2 to 5 degree rise is usually too small to feel uncomfortable, especially in a medium or large room. In a small bedroom or closet, you might notice it, but most people find the humidity reduction more important than the slight warmth. If you are sensitive to temperature, run the unit at night or in a different room.
Should I turn off my dehumidifier in winter?
Most homes do not need a dehumidifier in winter because cold air holds less moisture naturally. However, if you have a moisture problem in a basement or bathroom year-round, running it in winter is fine. The heat it produces is not wasted—it just adds to your home's warmth.
Can I use a dehumidifier and air conditioner at the same time?
You can, but it is inefficient. Your AC will have to work harder to cool the air that the dehumidifier just warmed. If humidity is the main problem, use the dehumidifier. If temperature is the main problem, use the AC. If both matter equally, a whole-house dehumidifier that vents outside is a better choice than running both units.
Does a dehumidifier use more energy because it heats the air?
The heating is a byproduct of the dehumidification process, not an extra feature that increases energy use. The dehumidifier uses the same amount of power whether or not you notice the warmth. However, if the warmth forces your AC to run longer, your total household energy use will increase.
What is the warmest a dehumidifier can make a room?
A portable dehumidifier alone will not raise room temperature more than 5 degrees or so. The exact amount depends on the unit's size, how long it runs, and how well the room is insulated. In a very small, sealed space, the effect might be slightly larger, but dehumidifiers are not designed to heat—the warmth is just a side effect.