For a damp basement up to about 1,300 sq ft, buy the AlorAir Sentinel HD55S. It removes 55 pints a day at the AHAM test condition, is Energy Star certified and is rated at 2.4 liters per kWh. That works out to about 3.4 cents of electricity per pint of water removed at the US average rate.
Our picks at a glance
From published specs and our sizing rules. Not lab tested.
- 1
Best overall
AlorAir Sentinel HD55S (55 pints AHAM, Energy Star)
Check price at AlorAirPaid link
- 2
Best value
AlorAir Sentinel HS35 (70 PPD, Energy Star)
Check price at AlorAirPaid link
- 3
No floor drain
AlorAir Sentinel HD35P (built-in pump)
70 pints per day at saturation
Check price at AlorAirPaid link
A typical basement dehumidifier draws about 500 W while the compressor runs. At 12 hours a day with the compressor on 60 percent of that time, that is 3.6 kWh a day, about $0.62 a day or $19 a month at 17.3 cents per kWh. The efficient units cost about the same per hour but remove more water per kWh, so they run fewer hours.
Size by square feet and how wet the space is, and pick gravity drain or a pump based on whether you have a floor drain. Our dehumidifier cost calculator runs the math at your state's rate.
Top picks, and why
AlorAir Sentinel HD55S (55 pints AHAM, Energy Star)
55 pints a day at AHAM, 2.4 L/kWh, Energy Star, up to 1,300 sq ft, around $649. It removes the most water per kWh of any unit we could confirm a rating for. Buy it for a finished or musty basement.
About $649 at AlorAir, checked Oct 12, 2026
Check price at AlorAirPaid link. We earn a commission at no cost to you.
AlorAir Sentinel HS35 (70 PPD, Energy Star)
Energy Star, 70 pints a day at saturation, up to 1,000 sq ft, around $450. Buy it for a crawl space or a smaller basement with a floor drain.
About $450 at AlorAir, checked Oct 12, 2026
Check price at AlorAirPaid link. We earn a commission at no cost to you.
70pints per day at saturation
AlorAir Sentinel HD35P (built-in pump)
- ENERGY STAR
- 35 pints/day
- 1,000 sq ft
- Built-in pump
+1 moreFewer
- Auto defrost
The same 70 pint class with a built-in condensate pump for around $466. The pump pushes water up to a sink or out a window, so you never empty a bucket.
- Built-in pump, drains up and out
- Low profile for crawl spaces
- Energy Star
- Sold on AlorAir's store, not Amazon
About $466 at AlorAir, checked Oct 16, 2026
Check price at AlorAirPaid link. We earn a commission at no cost to you.
What a basement dehumidifier costs to run
Cost per day is watts x hours x duty cycle / 1,000 x your rate. A 500 W unit running 12 hours at 60 percent duty uses 3.6 kWh a day: $0.62 at the 17.3 cent US average, $1.17 in California at about 32.5 cents and $0.45 in Louisiana at about 12.6 cents.
The number that cuts the bill is liters per kWh. At 2.4 L/kWh the HD55S uses about 0.2 kWh per pint (0.47 liters) of water removed, about 3.4 cents per pint at the US average. A less efficient unit runs longer to pull the same water.
Set it to 50 percent humidity, not lower. Each step below that adds run time with little benefit, and 50 percent is below the range where mold grows.
Size it: pints and square feet
Pint ratings come in two forms. AHAM pints are measured at 80 F and 60 percent humidity and are the fair comparison. Saturation pints are measured at 80 F and 100 percent humidity and run about twice as high. The HD55S is 55 pints AHAM and 120 at saturation.
Rough sizing for a basement: up to 1,000 sq ft and damp, a 70 PPD (saturation) unit. Up to 1,300 sq ft or wet with a musty smell, a 55 pint AHAM unit. A whole finished lower level up to about 2,900 sq ft, a 100 pint AHAM unit.
AlorAir Sentinel HS35 (70 PPD, Energy Star)
Energy Star, 70 PPD at saturation, gravity drain, around $450. AlorAir lists a 6-year limited warranty with the first 2 years full coverage.
About $450 at AlorAir, checked Oct 12, 2026
Check price at AlorAirPaid link. We earn a commission at no cost to you.
AlorAir Sentinel HD55S (55 pints AHAM, Energy Star)
55 pints AHAM, 2.4 L/kWh, Energy Star, 130 CFM, around $649. The best pick for most basements.
About $649 at AlorAir, checked Oct 12, 2026
Check price at AlorAirPaid link. We earn a commission at no cost to you.
100pints per day (AHAM)
AlorAir Sentinel HDi100 (100 pints AHAM, pump)
- 100 pints/day
- 2,900 sq ft
- Built-in pump
- Remote control
+1 moreFewer
- 5-year warranty
100 pints a day at AHAM with a built-in pump, around $1,399. One unit for a whole finished lower level instead of two smaller ones.
- 100 pints a day at AHAM
- Covers up to 2,900 sq ft
- Built-in pump with remote control
- Sold on AlorAir's store, not Amazon
About $1,399 at AlorAir, checked Oct 16, 2026
Check price at AlorAirPaid link. We earn a commission at no cost to you.
Gravity drain or pump
Gravity drain units need a floor drain or a sump pit lower than the unit. If you have one, skip the pump and save about $15 to $100 and one more part that can fail.
If water has to go up to a sink or out a window, buy a pump model like the HD35P or HDi100. Never rely on a bucket in a basement that needs a dehumidifier; it fills in a day.
Running it in a power outage
A dehumidifier is a low priority in an outage, but after a flood it matters. At about 500 W with the compressor running, a 2 kWh power station (about 1.7 kWh usable) runs it for about 3.5 hours. A small inverter generator runs it alongside a sump pump. The generator sizer shows what fits.
The bottom line
From published specs and our sizing rules. Not lab tested.
- 1
Best overall
AlorAir Sentinel HD55S (55 pints AHAM, Energy Star)
Check price at AlorAirPaid link
- 2
Best value
AlorAir Sentinel HS35 (70 PPD, Energy Star)
Check price at AlorAirPaid link
- 3
No floor drain
AlorAir Sentinel HD35P (built-in pump)
70 pints per day at saturation
Check price at AlorAirPaid link
Frequently asked questions
How much does it cost to run a dehumidifier in a basement?
About $0.62 a day or $19 a month at the US average of 17.3 cents per kWh, for a 500 W unit running 12 hours a day with the compressor on 60 percent of the time. Efficient Energy Star units remove more water per kWh and run fewer hours.
What size dehumidifier do I need for a basement?
About 70 pints a day (saturation rating) for a damp basement up to 1,000 sq ft, a 55 pint AHAM unit up to about 1,300 sq ft, and a 100 pint AHAM unit for up to about 2,900 sq ft. Wetter spaces need the next size up.
What humidity should a basement be?
Around 50 percent. Mold and dust mites thrive above about 60 percent, and going much below 50 adds run time and cost with little benefit.
What is the difference between AHAM and saturation pints?
AHAM pints are measured at 80 F and 60 percent humidity, the standard comparison. Saturation pints are measured at 100 percent humidity and are about double. Compare dehumidifiers on AHAM pints.
How long will a power station run a dehumidifier?
Divide usable watt-hours by running watts. A 2 kWh power station has about 1.7 kWh usable, so it runs a 500 W dehumidifier for about 3.5 hours with the compressor on the whole time. If the compressor cycles on 60 percent of the time, that stretches to about 5.7 hours.
Do I need a dehumidifier with a pump?
Only if there is no floor drain or sump pit lower than the unit. Gravity drain units like the AlorAir HS35 and HD55S need the hose to run downhill to a drain. If water has to go up to a sink or out a window, buy a pump model like the HD35P or HDi100, because a bucket in a damp basement can fill in a day.
Is an energy-efficient dehumidifier worth it?
Compare liters per kWh, because that sets the cost per pint of water removed. At 2.4 L/kWh the AlorAir HD55S uses about 0.2 kWh per pint, about 3.4 cents at 17.3 cents per kWh. A unit rated 1.8 L/kWh uses about 0.26 kWh per pint, about 4.5 cents, so it costs about a third more to pull the same water.
Why does my basement dehumidifier run all the time?
Usually it is undersized for the space, the humidity setpoint is below 50 percent, doors or windows to the outside are open, or the air filter is clogged. Water coming in through walls, a sump or bad gutters can also outpace any unit. Set it to 50 percent, clean the filter and close up the space, and if it still runs nonstop, step up a size or fix the water source.
How many hours a day should a basement dehumidifier run?
Let the humidistat decide: set it to 50 percent and the compressor cycles off once the air is dry enough. Our cost estimate assumes 12 hours a day with the compressor on 60 percent of that time, about 7.2 compressor hours and 3.6 kWh for a 500 W unit. A very wet basement in summer can run much longer.
Will a dehumidifier get rid of a musty basement smell?
It removes the damp conditions that cause it. The EPA advises keeping indoor humidity below 60 percent, ideally 30 to 50 percent, to limit mold growth, and a dehumidifier set to 50 percent holds a basement there. Mold that is already growing still has to be cleaned up and the water source fixed.
6 products are linked on this page. We have not lab-tested these products; picks are based on published specifications and our sizing rules. Amazon prices change, so we show a range and link to the live price. See our disclosure.
Size it for your home
Marcus Reed
Founder and Editor, CrunchYourDollars
Marcus Reed builds the sizing tools on CrunchYourDollars. He is a software engineer with a long-running PC hardware and power supply habit, which is where the watts, watt-hours and surge math on this site comes from. Product specs are pulled from manufacturer data sheets, electricity rates from the U.S. Energy Information Administration, and water chemistry rules from the Water Quality Association. He is not a licensed electrician or plumber: the tools show the math and the matching models so you can make the call, and anything involving your electrical panel should be checked by a licensed pro.
More about CrunchYourDollars and how we researchGet notified when we add tools
An occasional email when a new sizing tool goes live or the product database is refreshed. No spam, unsubscribe anytime.