Head to head
Dehumidifier vs air conditioner
These are the same machine pointed at different problems, and knowing which side effect you can live with settles the choice.
By Sawyer V. · Published
The short answer
They are the same refrigeration cycle with the heat put in different places. An air conditioner cools and dries, sending its waste heat outdoors. A dehumidifier dries and warms, because all its heat stays in the room. Use a thermometer-hygrometer for a day: if the temperature is the problem, cool it — 281.3 kWh a year. If only the humidity is, dry it — 283 kWh a year for a room-sized unit.
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At a glance
The picks, ranked
Tap any row to jump to the full reasoning. Prices are live from Amazon where we have them, and read “check price” where we don’t — never a number we cannot verify today.
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | If the temperature is the problem Midea Window Air Conditioner, 6,000 BTU CEER 16 and 281.3 kWh a year — it lowers temperature and removes moisture as a side effect. | A room that is genuinely too warm, humid or not | |
| 2 | If only the humidity is Vissani Dehumidifier, 27 pints/day 26.87 pints a day at 283 kWh a year — it removes the moisture without spending anything on cooling. | A room at a tolerable temperature that still feels clammy | |
| 3 | If you want one machine Midea Window Heat Pump Air Conditioner, 9,500 BTU CEER 17.6, 404.8 kWh a year, reverse-cycle heating — the highest CEER of any certified room unit. | A room that is hot in summer, damp in spring and cold in winter | |
| — | Where an air conditioner cannot help Waykar Dehumidifier, 49 pints/day 49.43 pints a day at 471 kWh a year — the case where cooling is simply the wrong tool. | A basement, crawl space or garage that is cool and wet |
A dehumidifier and an air conditioner are the same machine. Understanding that one sentence settles most of this comparison.
The mechanism
One cycle, two placements
Both run a vapor-compression refrigeration cycle: a cold evaporator coil that absorbs heat from air, and a hot condenser coil that dumps it.
An air conditioner splits them. The cold coil faces into the room; the hot coil faces outdoors. Room air is cooled, and because the coil is below the dew point, water condenses out and drains. The heat removed plus the compressor’s own energy goes outside.
A dehumidifier puts both coils in the room. Air passes over the cold coil, water condenses out, and the now-dry air passes over the hot coil on the way back. Net temperature change: slightly warmer, by the compressor’s power draw plus the latent heat released when vapor becomes liquid.
So the choice is genuinely about which side effect you want:
| Air conditioner | Dehumidifier | |
|---|---|---|
| Primary job | Lower temperature | Lower humidity |
| Side effect | Removes moisture | Warms the room slightly |
| Where heat goes | Outdoors | Stays in the room |
| Needs a window? | Yes, or a wall sleeve | No |
| Efficiency figure | CEER (tested) | IEF (tested) |
| Typical small unit | 281.3 kWh/yr | 283 kWh/yr |
| Noise rating published? | No | No |
Note the running costs. A small certified air conditioner is 281.3 kWh a year and a small certified dehumidifier is 283 kWh — within 1% of each other at $52 and $52 at 18.34¢/kWh. Cost is not the deciding factor; fitness for the problem is.
The test
Measure before you choose
A cheap thermometer-hygrometer left in the room for a day settles this better than any article can, because the two complaints feel almost identical.
- Warm and humid — an air conditioner. It fixes both at once, and dehumidifying is part of what it does.
- Comfortable temperature, high humidity — a dehumidifier. An air conditioner would have to overcool the room to get at the moisture.
- Cool and humid — a dehumidifier, clearly. This is the basement and shoulder-season case.
- Hot and dry — an air conditioner, or in a genuinely dry climate an evaporative cooler, which is the one machine that adds humidity on purpose.
The reason this matters is that humid air feels much warmer than it is. Your body sheds heat by evaporating sweat, and humid air has less spare capacity to absorb it — the mechanism behind every category on this site. A room at 74°F and 70% humidity is frequently diagnosed as a cooling problem when it is a moisture problem.
Dry mode
What the button on your air conditioner does
Most room air conditioners have a dry or dehumidify setting, and it is not a dehumidifier.
Dry mode runs the compressor with a reduced fan speed. Slower air spends longer against the cold coil, so a larger share of the cooling goes into condensing water rather than lowering air temperature. It genuinely removes more moisture per unit of cooling.
But it is still a cooling cycle. It will still lower the room temperature, and in a cool damp basement that is the opposite of what you want. It also cannot run without the outdoor half, so it needs the window installation a dehumidifier does not.
This one is not a DIY job
Running both at once is usually a mistake. An air conditioner already removes moisture; adding a dehumidifier to the same room means the dehumidifier’s waste heat becomes load for the air conditioner, which then works harder.
There are legitimate exceptions — a large house where a basement dehumidifier and an upstairs air conditioner serve different spaces, or a very humid climate where a whole-home dehumidifier supplements central cooling by design. Those are system decisions for an HVAC contractor.
If damp is persistent enough that you are considering both, find the water source first. A dryer venting indoors, missing extraction or groundwater will defeat either machine.
Say the unwelcome thing
Do not buy an air conditioner to fix a humidity problem.
It will work, and it is an expensive and uncomfortable way to do it.
To condense moisture, the coil has to be below the dew point — which means the machine has to keep cooling the air. In a room that was already at a comfortable temperature, that leaves you cold and still slightly clammy, cycling on and off, having paid to remove heat you wanted.
A dehumidifier removes the same water without spending anything on cooling, at an almost identical running cost — $52 a year against $52 for the small certified units.
Measure first. If the thermometer is fine and the hygrometer is not, 283 kWh a year of dehumidifier is the machine. If both are wrong, 281.3 kWh of air conditioner does both jobs.
In full
Every pick, and what is wrong with it
Published specifications only, each linked to the page it came from. Where a manufacturer publishes nothing, the row says so — we do not fill blanks in.
1. If the temperature is the problem
Midea Window Air Conditioner, 6,000 BTU
Midea · model MAW06S1KWT-A
CEER 16 and 281.3 kWh a year — it lowers temperature and removes moisture as a side effect.
The right machine whenever the thermometer, not the hygrometer, is the complaint.
281.3 kWh a year is about $52 at 18.34¢/kWh — the lowest annual figure of any certified room air conditioner at any capacity.
CEER 16, Most Efficient certified, 45% below the federal standard, at 31.6 lb with no support bracket required.
It dries the room too, because warm air hitting a cold coil condenses. That is genuine dehumidification — it is simply not free, since it happens as part of cooling you may not have needed.
What’s wrong with it
It occupies a window all season, and in a cool damp room it will overcool to dry.
Running cost — MAW06S1KWT-A
| Annual energy use | 281.3 kWh | ENERGY STAR certified figure |
|---|---|---|
| Annual cost | $52 | 281.3 × 18.34¢/kWh |
| Per cooling month | $13 | spread over a four-month season |
The annual figure is the certified value from the ENERGY STAR Certified Room Air Conditioners dataset, which models a standard cooling season rather than your actual summer. It is more useful than a nameplate wattage here, because a variable-speed compressor spends most of its life well below nameplate.
Rate: 18.34¢/kWh, the US average residential price for June 2026 (EIA Electric Power Monthly, Table 5.3). Yours will differ — swap it in: (watts ÷ 1000) × hours × your rate.
| Cooling capacity | 6,000 BTU/h |
|---|---|
| CEER | 16 |
| Annual energy use | 281.3 kWh/yr |
| vs federal standard | 45% less energy |
| Dimensions | 12.1 H x 16.0 W x 13.3 D in |
| Weight | 31.6 lb |
| Installation | Does not straddle the windowsill |
| Support bracket | Not required |
| Compressor | Variable speed |
| Refrigerant | R-32 |
| ENERGY STAR | Certified, and on the Most Efficient list |
Every figure above is from ENERGY STAR Certified Room Air Conditioners dataset. Blanks are shown as “not published” rather than filled in.
2. If only the humidity is
Vissani Dehumidifier, 27 pints/day
Vissani · model VAD25S1AWTS
26.87 pints a day at 283 kWh a year — it removes the moisture without spending anything on cooling.
The case people most often get wrong: a basement or a shut-up house in spring, where the temperature is fine and the air is not.
283 kWh a year, about $52 at 18.34¢/kWh — almost identical to the air conditioner above, for a completely different job.
26.87 pints a day at 2.01 L/kWh, the category median, in the smallest mainstream certified capacity.
The side effect runs the other way: all its electrical energy becomes heat in the room, plus the latent heat released as water condenses. The room feels cooler because sweat can evaporate again; the thermometer goes very slightly up.
What’s wrong with it
It warms the room slightly, and it does nothing if the air is genuinely too hot.
Running cost — VAD25S1AWTS
| Annual energy use | 283 kWh | ENERGY STAR certified figure |
|---|---|---|
| Annual cost | $52 | 283 × 18.34¢/kWh |
| Per cooling month | $13 | spread over a four-month season |
The annual figure is the certified value from the ENERGY STAR Certified Dehumidifiers dataset, which models a standard cooling season rather than your actual summer. It is more useful than a nameplate wattage here, because a variable-speed compressor spends most of its life well below nameplate.
Rate: 18.34¢/kWh, the US average residential price for June 2026 (EIA Electric Power Monthly, Table 5.3). Yours will differ — swap it in: (watts ÷ 1000) × hours × your rate.
| Water removal | 26.87 pints/day (DOE Appendix X1) |
|---|---|
| Efficiency (IEF) | 2.01 L/kWh |
| Annual energy use | 283 kWh/yr |
| Refrigerant | HFC-32 (GWP 675) |
| Connected | No |
| Noise | Not published in the certified dataset |
| ENERGY STAR | Certified |
Every figure above is from ENERGY STAR Certified Dehumidifiers dataset. Blanks are shown as “not published” rather than filled in.
3. If you want one machine
Midea Window Heat Pump Air Conditioner, 9,500 BTU
Midea · model MAH09B1AGR
CEER 17.6, 404.8 kWh a year, reverse-cycle heating — the highest CEER of any certified room unit.
Most room air conditioners have a dry or dehumidify mode, and it is worth being precise about what that is.
Dry mode runs the compressor with a reduced fan speed. Slower air across the coil means more condensation per unit of cooling, so it removes proportionally more water. It is still refrigeration, and it still cools the room.
CEER 17.6 and 404.8 kWh a year, about $74 at 18.34¢/kWh, 80% below the federal standard and reverse-cycle for winter.
One machine covering three seasons is a real argument. Just do not expect dry mode to behave like a dehumidifier in a room you do not want colder.
What’s wrong with it
129 lb over a saddle mount, and its dry mode is still a cooling cycle.
Running cost — MAH09B1AGR
| Annual energy use | 404.8 kWh | ENERGY STAR certified figure |
|---|---|---|
| Annual cost | $74 | 404.8 × 18.34¢/kWh |
| Per cooling month | $19 | spread over a four-month season |
The annual figure is the certified value from the ENERGY STAR Certified Room Air Conditioners dataset, which models a standard cooling season rather than your actual summer. It is more useful than a nameplate wattage here, because a variable-speed compressor spends most of its life well below nameplate.
Rate: 18.34¢/kWh, the US average residential price for June 2026 (EIA Electric Power Monthly, Table 5.3). Yours will differ — swap it in: (watts ÷ 1000) × hours × your rate.
| Cooling capacity | 9,500 BTU/h |
|---|---|
| Heating mode | Yes, reverse cycle |
| CEER | 17.6 |
| Annual energy use | 404.8 kWh/yr |
| vs federal standard | 80% less energy |
| Dimensions | 20.9 H x 25.0 W x 41.2 D in |
| Weight | 129.0 lb |
| Installation | Straddles the windowsill (saddle style) |
| Support bracket | Not required |
| Compressor | Variable speed |
| Refrigerant | R-32 |
| ENERGY STAR | Certified, and on the Most Efficient list |
Every figure above is from ENERGY STAR Certified Room Air Conditioners dataset. Blanks are shown as “not published” rather than filled in.
Skip this one
Waykar Dehumidifier, 49 pints/day
Waykar · model CTH150D
49.43 pints a day at 471 kWh a year — the case where cooling is simply the wrong tool.
Marked skip only because it is the wrong size for most rooms — the category is exactly right for the space it is built for.
A basement at 65°F and 75% relative humidity has no temperature problem at all. Running an air conditioner there would take a comfortable room and make it a cold one, at far higher cost, to get at the moisture.
2.20 L/kWh and 471 kWh a year, about $86 at 18.34¢/kWh, Most Efficient certified.
The basement case in full — and plumb it to drain.
What’s wrong with it
Basement capacity. In a room you occupy it is oversized and louder than it needs to be.
Running cost — CTH150D
| Annual energy use | 471 kWh | ENERGY STAR certified figure |
|---|---|---|
| Annual cost | $86 | 471 × 18.34¢/kWh |
| Per cooling month | $22 | spread over a four-month season |
The annual figure is the certified value from the ENERGY STAR Certified Dehumidifiers dataset, which models a standard cooling season rather than your actual summer. It is more useful than a nameplate wattage here, because a variable-speed compressor spends most of its life well below nameplate.
Rate: 18.34¢/kWh, the US average residential price for June 2026 (EIA Electric Power Monthly, Table 5.3). Yours will differ — swap it in: (watts ÷ 1000) × hours × your rate.
| Water removal | 49.43 pints/day (DOE Appendix X1) |
|---|---|
| Efficiency (IEF) | 2.20 L/kWh |
| Annual energy use | 471 kWh/yr |
| Refrigerant | HFC-32 (GWP 675) |
| Connected | No |
| Noise | Not published in the certified dataset |
| ENERGY STAR | Certified, and on the Most Efficient list |
Every figure above is from ENERGY STAR Certified Dehumidifiers dataset. Blanks are shown as “not published” rather than filled in.
We are not linking a buy button for this one. If you want to look at it anyway, it is easy enough to find — but we would rather send you to something that fits your room.
Questions people actually ask
Frequently asked
Does an air conditioner work as a dehumidifier?
Yes, as a side effect — warm air hitting a cold coil condenses, and the water drains away. The catch is that it has to keep cooling to do it, so in a room already at a comfortable temperature you end up cold to get dry.
Does a dehumidifier cool a room?
No, it warms it slightly. Both coils are in the room, so all the electrical energy becomes heat, plus the latent heat released when vapor condenses. The room feels cooler because your sweat can evaporate again, but the thermometer goes up a little.
Which is cheaper to run, a dehumidifier or an air conditioner?
They are almost identical at small sizes. A certified 6,000 BTU air conditioner is 281.3 kWh a year and a certified 27-pint dehumidifier is 283 kWh — $52 against $52 at 18.34¢/kWh. Choose on fitness for the problem, not cost.
What does dry mode on an air conditioner actually do?
It runs the compressor with a reduced fan speed, so air spends longer against the cold coil and more of the cooling goes into condensing water. It removes more moisture per unit of cooling — but it is still a cooling cycle and still lowers the room temperature.
Should I run a dehumidifier and an air conditioner together?
Usually not in the same room. The air conditioner already removes moisture, and the dehumidifier's waste heat becomes extra load for it. Exceptions exist in large houses and very humid climates, but those are system decisions for an HVAC contractor.
How do I tell which one I need?
Leave a thermometer-hygrometer in the room for a day. Warm and humid means an air conditioner. Comfortable temperature with high humidity means a dehumidifier. Cool and humid — the basement case — means a dehumidifier, clearly. Why humid air feels hotter.
Sources
Where these numbers came from
Read next
Where to go from here
Back to Dehumidifiers, or read how we pick.