Energy Efficient Dehumidifiers

The one specification that matters, and where to find it

A dehumidifier is a refrigeration machine that runs for months at a time. Its purchase price is a one-off; its electricity bill is not. The specification that governs that bill is the Integrated Energy Factor (IEF) - liters of water removed per kilowatt-hour of electricity consumed. Higher is better. A unit at 2.01 L/kWh removes about 18% more water per unit of electricity than one at 1.70.

Manufacturers rarely put IEF on the box and Amazon listings essentially never do. But every certified model is in the ENERGY STAR certified products database with its IEF, its federal-test capacity and its annual energy use in kWh - and you can look up any model number in it before you buy. That database is the entire basis of this page. We pulled all 550 rows.

The badge is graded on a curve, and nobody explains that

Here is the trap. A 25-pint unit with an IEF of 1.85 carries the Most Efficient badge. A 32-pint unit with an IEF of 2.15 - measurably better at converting electricity into dry air - does not. That is not an error. The Most Efficient thresholds are set within capacity class, so IEF numbers are only comparable between units of similar size. We worked the thresholds out from the certified data itself:

Two things fall out of that table. First, in the 25-pint class the line is razor thin: 1.85 earns the badge and 1.84 misses it, a difference of well under one percent that decides whether a sticker goes on the box.

Second, and more usefully: there is no ENERGY STAR Most Efficient dehumidifier in the 26-to-35 pint class at all. Thirty-eight certified models, the best of them at 2.15 L/kWh, and not one qualifies. If you have been searching for an efficient 30-pint or 32-pint dehumidifier and coming up empty, that is why. It is not you.

How we picked these

We have not tested these machines. We do not own them and we have no lab. What we did instead was cross-reference the federal certification data against what is actually purchasable, and the criteria are, in order:

1. Is the certified figure real and attributable? Every IEF and kWh figure here comes from the ENERGY STAR certified products database against a specific model number. Nothing is inferred from a nameplate wattage.
2. Can we prove the listing is that model? This eliminated more candidates than anything else. If the retail listing does not state a model number we cannot match, the certificate is unverifiable and the product is not recommended.
3. Is it purchasable right now? Checked against live listing data, not memory.
4. Does the efficiency actually matter at that capacity? An efficient machine too small for the room runs continuously and never reaches setpoint, which costs more than an ordinary machine that cycles.

What the four actually cost to run

Annual energy use below is ENERGY STAR’s published figure for that exact model number. The dollar column is that figure multiplied by 18.34 cents per kWh, the US average residential electricity price. The arithmetic is deliberately visible so you can redo it with your own rate.

Note what that table does not show: a neat relationship between the badge and the bill. The cheapest unit to run is the Midea Cube 20, at about $46 a year - and it has the worst IEF of anything listed. It is cheap to run because it is small, not because it is efficient. The only Most Efficient unit here costs $6 a year more.

Efficiency and a low bill are two different questions

This is the distinction that makes most “energy efficient dehumidifier” advice useless. There are two questions and they have different answers:

• “Which unit uses the least electricity?” Almost always the smallest one that can hold your space. Capacity drives consumption far harder than efficiency does - the 50-pint Whirlpool costs roughly twice as much a year to run as the 25-pint, and they share a brand and a control panel.
• “Which unit wastes the least electricity?” That is IEF, and that is what the badge is about.

Buying the smallest unit is the right instinct only up to the point where it can keep up. Below that point it runs continuously, never reaches setpoint and quietly costs more than the larger machine that cycles off. Getting that line right is the whole of what size dehumidifier do I need, and it matters more to your bill than any badge on this page.

The efficiency list is full of brands that do not exist

Sort the certified portable models by IEF and the top of the table is almost entirely names you have never heard of. That is worth understanding before you buy one, because the federal data explains exactly what is going on.

Twelve portable model numbers in the database are certified under more than one brand name. The most striking is model AS-CSJ72XK-5WT-OL - 25.00 pints/day, IEF 2.04, 257 kWh a year, Most Efficient. It appears in the database thirteen times, under thirteen different brand names: CONCETTA, DUMOS, Gianna, IULULU, JIOABL, KMFurnila, NEWBULIG, OLIXIS, SMUG, SUMELL, Sweetcrispy, ZUNMOS and edx. All thirteen list the same ENERGY STAR partner: Zhejiang Hengjian Home Furnishing Co., Ltd. The same thirteen brands also share two further model numbers between them.

This is not fraud and the certification is real - it is one genuinely efficient machine sold under thirteen storefronts. But it does mean that comparing four of those “different” dehumidifiers on Amazon is comparing one dehumidifier four times, and that whichever brand you pick, the after-sales relationship is with a storefront rather than a manufacturer. We do not recommend them here because their listings carry no model number, so there is no way to confirm the unit that arrives is the certified one.

The pint number on the listing is not the pint number on the certificate

In 2019 the Department of Energy changed how portable dehumidifiers are tested. Under the current federal test method they are rated at 65°F rather than 80°F, to better reflect a basement. There is less moisture in cooler air, so rated capacities fell across the board - ENERGY STAR says so directly.

Retail listings did not follow. Waykar tops the Most Efficient table with several entries, and the highest capacity Waykar has certified with ENERGY STAR is 50.00 pints per day. Its Amazon listings advertise 80-pint and 150-pint units. We could not find, on the listings themselves, what test conditions produce the larger figure, so we are not going to guess at one - but a “150 pint” dehumidifier and a federally-rated 50-pint dehumidifier can be the same machine described two ways.

The practical consequence: when you compare capacities, compare federal-test figures or compare listing figures, and never mix the two. Every capacity in the table above is the federal one.

Where the Midea Cube lands

The Midea Cube is the unit this site has recommended most often and the one most recommended across the category generally. It is worth being straight about where it sits here: none of Midea’s 47 certified rows is Most Efficient. Its IEF range is 1.70 to 2.08, and the 35 and 50-pint models at 2.01 are respectable without being remarkable.

That does not make it a bad buy, and we have not changed our view of it in the Cube review. It is bought for its adjustable bucket, its nesting body and its drainage, and those are real advantages that no efficiency figure captures. But if your reason for buying is specifically the electricity bill, the Cube is not the answer to that question and its listing implies otherwise by saying “Energy star” in the title.

What we would actually do

Buy a hygrometer first. If the room reads inside 30-50%, every unit on this page is solving a problem you do not have, and the cheapest possible running cost is zero. We make that case at length in is a dehumidifier worth it.

If it genuinely is damp: size the unit to the space first and treat efficiency as the tie-breaker between two units that both fit, never as the reason to buy a smaller one. For a single room, the WHAD251AW is the only Most Efficient portable we could tie to a purchasable listing, and it was down to one unit in stock when we checked - if it is gone, the 32-pint model is a better machine than its missing badge suggests. For a basement, capacity and a pump will save you more than any IEF difference, because the dehumidifier that gets unplugged after three weeks of carrying buckets upstairs has an efficiency of zero.

And whatever you are looking at, search its model number in the ENERGY STAR certified products database before you buy. It takes about thirty seconds and it is the only place the real number is written down.