What size dehumidifier do I need for a basement?

For a basement under 2,000 sq ft, ENERGY STAR says 20 to 30 certified pints a day if it is slightly to moderately damp, 25 to 40 if very damp and 30 to 50 if wet. Most people should buy a certified 50-pint: it covers all three, the Midea 50 Pint was $259.99 on October 17, 2026 (only $30 more than the cheapest certified 25-pint we checked, for twice the certified pints), and ENERGY STAR says oversizing beats undersizing.

What size dehumidifier do I need for 1,000 square feet?

It depends on dampness, not just area. Under 2,000 sq ft, ENERGY STAR says 20 to 30 certified pints if damp, 25 to 40 if very damp, 30 to 50 if wet. A certified 50-pint covers every case.

Why does the box say 80 pints when the certified number is 25?

Most boxes quote a test at 95°F and 90% humidity, or the old 80°F test. The current DOE test uses 65°F and 60% humidity, like a basement, and cooler air holds less water, so the certified number is smaller. Of 22 certified Amazon bestsellers we checked, 16 print at least three times their certified pints.

How do old and new dehumidifier sizes compare?

ENERGY STAR's conversion: an old 30-pint is about a new 20, an old 50 about 30, an old 70 about 40 to 45, and an old 90 about 55.

Is it bad to buy a dehumidifier that is too big?

No. ENERGY STAR says it is better to oversize than undersize. A bigger unit reaches your humidity setting faster and then shuts off.

What humidity should I set it to?

EPA's target is below 60% relative humidity, ideally 30 to 50%. Set the humidistat to 50% and check with a cheap hygrometer across the room.

Will a dehumidifier work in a cold basement?

Standard units can frost up below about 65°F, says ENERGY STAR. Look for a unit that lists a lower operating floor, such as 41°F.

What Size Dehumidifier Do I Need?

Size it by how damp the space is, in certified pints, not the number on the box. For a space under 2,000 sq ft, ENERGY STAR says 20 to 30 pints a day if it's slightly to moderately damp, 25 to 40 if very damp, and 30 to 50 if wet. For most basements, buy a certified 50-pint: the Midea 50 Pint was $259.99 at Amazon.com on October 17, 2026, only $30 more than the cheapest certified 25-pint we checked, for twice the certified pints. ENERGY STAR says it's better to oversize than undersize.[1]

Most basements, any dampness

Midea 50 Pint (MAD50C1AWS-A)

$259.99 on Amazon, October 17, 2026

Certified at 49.74 pints, so the box and the list agree. Costs $30 more than the cheapest certified 25-pint we checked, for twice the water. You supply a garden hose to a floor drain.
Check price on Amazon
49.74 pints/day certified · 2.01 L/kWh · box says 50
Drain is higher than the unit

Midea 50 Pint with Pump (MAD50P1AWS-A)

$241.72 on Amazon, October 17, 2026

The same certified 49.74 pints with a built-in pump, to push water up to a sink or out a window. It was $18.27 less than the plain model on October 17, 2026.
Check price on Amazon
49.74 pints/day certified · 2.01 L/kWh · box says 50
Bedroom, closet or small bathroom

Waykar PD160B-PRO

$165.97 on Amazon, October 17, 2026

Sold as "34 pints", certified at 10.16. That is the right size for one small room; ENERGY STAR Most Efficient.
Check price on Amazon
10.16 pints/day certified · 1.91 L/kWh · box says 34

Prices are Amazon's on October 17, 2026; all three are sold by Amazon.com and were in stock that day. Affiliate links; we earn a commission at no cost to you.

By Erin Rose · Updated October 17, 2026

01 / Size chart

ENERGY STAR's sizing table, in certified pints per day

ENERGY STAR's sizing table, in certified pints per day
How damp	What it looks like	Under 2,000 sq ft	Over 2,000 sq ft
Slightly to moderately damp	Feels damp, musty smell now and then. 50–75% humidity.	20–30 pints	30+ pints
Very damp	Always feels and smells damp; damp spots on walls and floor. 75–90% humidity.	25–40 pints	40+ pints
Wet	Walls or floor sweat, or water seeps in; laundry drying. 90–100% humidity.	30–50 pints	50+ pints

"Remember, it's better to oversize than undersize!" — ENERGY STAR. Pints are on the current DOE test.[1]

02 / The verdict

Why a 50-pint is the right buy for most basements

Price: the certified 50-pint Midea was $259.99; the certified 25-pint Levoit was $229.99 and the 24-pint Waykar YDZ-80 $235.99 (all at Amazon.com, October 17, 2026). That is $30 more for twice the certified pints.
Energy per pint of water: the Midea removes 2.01 liters per kWh, the Levoit 1.88. So for the same damp basement, the 50-pint uses a little less power to remove the same water.
ENERGY STAR's yearly figures (about $84 for the 50-pint vs $45 for the 25-pint) assume each runs at its full rated output, so the 50-pint is removing twice the water. They are not the cost of drying the same room.
ENERGY STAR's own advice: "it's better to oversize than undersize."
When a 25-pint makes sense: a small, slightly damp space where you want a quieter, lighter unit. The Levoit has a built-in pump.

03 / Read the box

What the box says vs what is certified

Six certified units sold by Amazon.com. Buy by the certified column.

What the box says vs what is certified
Unit	Box says	Certified	L per kWh	Price	Buy
Midea 50 Pint	50 pints	49.74 pints	2.01	$259.99	Check price
Midea 50 Pint with Pump	50 pints	49.74 pints	2.01	$241.72	Check price
Levoit LDH-H251SENERGY STAR Most Efficient	84 pints	24.54 pints	1.88	$229.99	Check price
Waykar YDZ-80	80 pints	24 pints	1.76	$235.99	Check price
Waykar PD160B-PROENERGY STAR Most Efficient	34 pints	10.16 pints	1.91	$165.97	Check price
Kesnos CTH30B	30 pints	9.2 pints	1.7	$131.85	Check price

Certified pints and liters per kWh are from the ENERGY STAR list. Box figure is the largest pint number on the Amazon listing. Prices October 17, 2026.[3]

04 / Old vs new

Old box numbers vs today's label

Since 2019 portable units are tested at 65°F instead of 80°F. Cooler air holds less water, so the same machine now rates lower. ENERGY STAR's conversion:[2]

Old box numbers vs today's label
Old box (80°F test)	Today's label (65°F test)
30 pints	about 20 pints
40 pints	about 25 pints
50 pints	about 30 pints
55 pints	about 30–35 pints
60 pints	about 35 pints
70 pints	about 40–45 pints
90 pints	about 55 pints

05 / Your space

Special cases

Cold basement (below 65°F). ENERGY STAR warns that frost can form on the coils below 65°F and suggests a unit rated for lower temperatures. The Waykar YDZ-80 lists a 41°F floor; it certifies at 24.0 pints ($235.99).
Over 2,000 sq ft. ENERGY STAR's large-room column: 30+ pints if damp, 40+ very damp, 50+ wet. Above 50 pints, the certified units are whole-home models that duct into the air handler.
Crawl space. Fix the vapor barrier on the dirt first. A 50-pint portable on a pump can work if it sits level and you can reach the filter.
Water coming through the wall. A dehumidifier dries the air. It can't keep up with water seeping in; fix the grading, gutters or foundation first.
Replacing an old unit. If your old box is from before 2020, use the conversion table above: an old 50-pint is about a 30 on today's label, an old 70 about 40 to 45.

06 / Questions

Frequently asked

What size dehumidifier do I need for a basement?: For a basement under 2,000 sq ft, ENERGY STAR says 20 to 30 certified pints a day if it is slightly to moderately damp, 25 to 40 if very damp and 30 to 50 if wet. Most people should buy a certified 50-pint: it covers all three, the Midea 50 Pint was $259.99 on October 17, 2026 (only $30 more than the cheapest certified 25-pint we checked, for twice the certified pints), and ENERGY STAR says oversizing beats undersizing.
What size dehumidifier do I need for 1,000 square feet?: It depends on dampness, not just area. Under 2,000 sq ft, ENERGY STAR says 20 to 30 certified pints if damp, 25 to 40 if very damp, 30 to 50 if wet. A certified 50-pint covers every case.
Why does the box say 80 pints when the certified number is 25?: Most boxes quote a test at 95°F and 90% humidity, or the old 80°F test. The current DOE test uses 65°F and 60% humidity, like a basement, and cooler air holds less water, so the certified number is smaller. Of 22 certified Amazon bestsellers we checked, 16 print at least three times their certified pints.
How do old and new dehumidifier sizes compare?: ENERGY STAR's conversion: an old 30-pint is about a new 20, an old 50 about 30, an old 70 about 40 to 45, and an old 90 about 55.
Is it bad to buy a dehumidifier that is too big?: No. ENERGY STAR says it is better to oversize than undersize. A bigger unit reaches your humidity setting faster and then shuts off.
What humidity should I set it to?: EPA's target is below 60% relative humidity, ideally 30 to 50%. Set the humidistat to 50% and check with a cheap hygrometer across the room.
Will a dehumidifier work in a cold basement?: Standard units can frost up below about 65°F, says ENERGY STAR. Look for a unit that lists a lower operating floor, such as 41°F.

References

Sources

7 references · checked October 17, 2026

1
ENERGY STAR: Dehumidifiers (sizing table)

Read October 17, 2026. Sizing table; "better to oversize than undersize"; frost below 65°F.
2
ENERGY STAR: Dehumidifier testing and capacity

Read October 17, 2026. 65°F test; old-to-new conversion table.
3
ENERGY STAR certified dehumidifiers dataset (Socrata mgiu-hu4z), 550 rows pulled 2026-09-19

Certified pints, liters per kWh and yearly energy for each unit.
4
10 CFR Part 430, Subpart B, Appendix X1 — Uniform Test Method for Measuring the Energy Consumption of Dehumidifiers

The federal test procedure (65°F, 60% humidity for portable units).
5
A Brief Guide to Mold, Moisture, and Your Home

Humidity target below 60%, ideally 30 to 50%.
6
Our decode of 40 Amazon dehumidifier bestsellers against the ENERGY STAR list

Box claim vs certified pints for every listing.
7
Amazon listings (price, seller, stock)

Read live October 17, 2026.