A dehumidifier can remove that dampness from a basement or laundry room and prevent sticky issues that come with too much moisture in the air. Humidity levels above 50 percent can breed dust mites, mildew, and mold, triggering allergies or other health problems. What size dehumidifier do I need? Get details from Dehumidifier buyers guide.
Types – Dehumidifier buyers guide
There are three major types of dehumidifiers:
- Compressor based dehumidifiers
- Thermo-electric dehumidifiers
- Desiccant dehumidifiers
Full-size compressor based dehumidifiers (such as those in the photo above) are capable of removing several gallons of water from the air each day. Most thermo-electric and desiccant units can remove only a few ounces per day at best.
Compressor based units can be used to dehumidify any (reasonably) sized space at any humidity level. Most thermo-electric and desiccant units can only be used to dehumidify small spaces (like a closet, for example) and only if the humidity level in that space isn’t very high.
Because thermo-electric and desiccant units simply will not work for most people in most situations we’re going to leave our discussion of them for later.
Our focus for most of this guide will be on full-size compressor based dehumidifiers – the only type of dehumidifier that will serve the needs of most people in most situations. This is also the type of dehumidifier that most people traditionally think of when they hear the word “dehumidifier”.
A Critical Step – Dehumidifier buyers guide
We’ll get to our top dehumidifier picks (our recommendations of the best dehumidifiers) in just a moment, but before we do, it’s necessary that we first go over new government standards for dehumidifiers.
A clear understanding of these new standards will be absolutely critical for you to determine exactly which model dehumidifier you need to buy.
New Dehumidifier Standards – Dehumidifier buyers guide
Dehumidifiers sold in the United States are manufactured according to US government standards. More specifically, the US Department of Energy (DOE) gives certain requirements for manufacturers to follow in order to be able to sell their dehumidifiers within the United States.
There are, broadly speaking, two basic requirements:
- that the pints/day specification be given according to testing standards outlined by the DOE
- that the dehumidifier meets certain energy efficiency requirements
A. The Pints/Day Requirement
In the past, dehumidifiers were officially tested at 80°F and 60% RH. Since June 13, 2019 dehumidifiers are required to be tested at a lower temperature – 65°F – but the same humidity level – 60% RH.
This results in a decrease in the manufacturer pints/day specification for any particular model dehumidifier.
A 70 pint dehumidifier before June 13, 2019 is a 50 pint dehumidifier after June 13, 2019.
Why the decrease? Why the lower pints/day specification?
Because colder air contains less moisture than warmer air at the same humidity level. A block of air at 65°F and 60% RH contains less moisture than the same block of air at 80°F and 60% RH.
A 70 pint dehumidifier tested before June 13, 2019 was placed in a room with air at 80°F and 60% RH. That block of air contained enough moisture for the dehumidifier to be able to remove 70 pints of moisture in a day.
The same 70 pint dehumidifier tested after June 13, 2019 is placed in a room with air at 65°F and 60% RH. That block of air contains less moisture and so the same “70 pint dehumidifier” is now only able to remove 50 pints from that air per day.
Since 65°F and 60% RH is the new official testing standard, what used to be called a “70 pint dehumidifier” is now called a 50 pint dehumidifier.
The Frigidaire FFAD5033W1, for example, removes approx. 70 pints of moisture per day at 80°F and 60% RH. This very same model removes 50 pints of moisture per day at 65°F and 60% RH.
In the past, the FFAD5033W1 would have been sold as a 70 pint dehumidifier. Today, according to new testing standards, it is required to be sold as a 50 pint dehumidifier.
|Model||At 80°F and 60% RH (pre-2019)||At 65°F and 60% RH (post-2019)|
|Frigidaire FFAD5033W1||70 pints/day||50 pints/day|
|hOmeLabs HME020031N||70 pints/day||50 pints/day|
|Black+Decker BDT50WTB||70 pints/day||50 pints/day|
B. The Energy Efficiency Requirement
Now that you’re familiar with how pints/day requirements have changed over time, we can take a look at how the DOE’s energy efficiency requirements for dehumidifiers have changed over time.
In the past, the requirements looked like this:
|Pints/day (Capacity)||Energy Factor (EF) – L/kWh|
Beginning June 13, 2019 the requirements are now this:
|Pints/day (Capacity)||Integrated Energy Factor (IEF) – L/kWh|
Note the differences between these two tables:
- the pints/day categories
- the use of “energy factor” vs “integrated energy factor” in the right column
- the actual energy efficiency requirements – the numbers in the right column
The pints/day categories have changed because pints/day testing and specification requirements have changed as we discussed earlier.
The energy efficiency requirements are now outlined in terms of “integrated energy factor” instead of “energy factor”.
Energy factor simply measures the Liters the dehumidifier removes per kWh of energy use while it is actively dehumidifying.
Integrated energy factor involves a complex equation in which the dehumidifier is tested on various settings and during various time intervals, but basically it boils down to this:
IEF = liters of water removed / energy used while the dehumidifier is actively dehumidifying + energy used in standby and other low power modes
IEF is essentially a more nuanced – a more accurate version of EF. IEF is also the less forgiving metric as it accounts for more cases of energy use than EF (such as when the dehumidifier’s compressor is off and only its fan is running).
The end result is that the latest DOE energy efficiency requirements are more stringent than ever as the DOE is pushing manufacturers towards making more energy efficient dehumidifiers.
All dehumidifiers manufactured AFTER June 19, 2019 HAVE TO adhere to these more strict energy efficiency guidelines to be able to be sold in the United States. This means that you absolutely want to buy a dehumidifier manufactured after this date.
Rest assured, all top rated dehumidifiers we recommend fit this requirement.
New Energy Star Requirements – Dehumidifier buyers guide
Completely separate from DOE energy efficiency requirements, are Energy Star energy efficiency requirements.
Energy star certification has been available to dehumidifier manufacturers for close to 20 years now (since January, 2001). Over that time period several different versions of energy star requirements have been published.
Version 4.0 was effective as of October 25, 2016. The requirements were as follows:
|Pints/day (Capacity)||Energy Factor (EF) – L/kWh|
|< 75||≥ 2.00|
|75 to ≤ 185||≥ 2.80|
Note that the pints/day categories in the table above involved testing at 80°F and 60% RH and EF is used instead of IEF.
Version 5.0 is effective as of October 18, 2019. The requirements now are as follows:
|Pints/day (Capacity)||Integrated Energy Factor (IEF) – L/kWh|
|≤ 25.00||≥ 1.57|
|25.01 to 50||≥ 1.80|
|≥ 50||≥ 3.30|
Note that the pints/day categories in the table above involves testing at 65°F and 60% RH and IEF is used instead of EF.
All dehumidifiers sold as Energy Star compliant after October 18, 2019 have to fit these new more stringent requirements.
Note that there are still models on the market today that have an Energy Star sticker and are sold as being Energy Star compliant that do NOT meet version 5.0 requirements. At the time that they were manufactured (when the Energy Star sticker was applied) and at the time that they were first sold (when Energy Star compliancy was added to their product description) they may very well have been Energy Star compliant according to version 4.0 requirements.
But they are now no longer Energy Star compliant and their product descriptions simply haven’t been updated yet.
Rest assured that all of the models we recommend are fully Energy Star compliant according to version 5.0 requirements.
Dehumidifier Capacity and Area of Coverage
Note: Even if the concept of dehumidifier capacity isn’t completely new to you, we ask that you bear with us through the next section of the guide as we explain how our view on this concept (and how it should be applied in selecting a particular dehumidifier model) is much different than the view held by most other consumer publications and even many manufacturers.
We mentioned at the beginning of this guide that compressor based dehumidifiers are capable of removing several gallons of water from the air per day.
How much water (moisture) a dehumidifier can remove from the air per day is referred to as the dehumidifier’s capacity. A dehumidifier that can remove 6.25 gallons of water from the air per day is said to have a capacity of 6.25 gallons. Or is it?
Dehumidifier manufacturers generally don’t use gallons to specify the capacity of their dehumidifiers. It’s too large of a volume. Instead, they use pints. Of course, a pint is simply an eighth of a gallon.
So, a dehumidifier having a capacity of 6.25 gallons per day is simply referred to as a 50 pint dehumidifier.
50 pint dehumidifiers are the most common type of compressor based dehumidifier, followed by 35 pint dehumidifiers (35 pints = 4.375 gallons) and 22 pint dehumidifiers (22 pints = 2.75 gallons). There are also dehumidifiers on the market that stray somewhat from these general capacity standards. It’s not uncommon to find dehumidifiers rated to remove 45, 30, or 20 pints of moisture per day, for example.
What Capacity Dehumidifier Should You Buy?
At this point in most other dehumidifier buyer’s guides the author of the guide might point you to a size chart (or table) to help you determine what capacity dehumidifier you need to buy.
The chart might require you to
- Select the dampness of the space you need to dehumidify
- Select the square footage of that space
- Match the selected dampness row with the selected square footage column – this gives the capacity of the dehumidifier you’re advised to buy
Many manufacturers give a more simplified size chart to help you choose which dehumidifier to buy.
- Some charts suggest dehumidifier capacity based on dampness alone
- Other charts only use square footage to suggest which size dehumidifier to buy
Unlike most other consumer publications and many manufacturers, we do not recommend that you use a chart or table to help you decide what capacity dehumidifier to buy.
Why do we disagree with the use of such methods? See the 6 reasons below.
1. Charts/tables usually have a limited range. They may begin at 1,500 square feet and end at 4,500 square feet. What if the space you need to dehumidify is smaller than 1,500 square feet? What if it’s larger than 4,500 square feet? These charts fail to make recommendations for spaces that fall outside of the given range.
2. Charts usually fail to take into account the height of the space you need to dehumidify. Rooms with higher ceilings contain more air than rooms with lower ceilings – something that a chart or table doesn’t take into account at all. Much more appropriate would be recommendations based on the volume (measured in cubic feet ), not the area of the space you need to dehumidify.
3. Charts fail to take into account dehumidifier CFM – the CFM of the dehumidifier’s intake fan (the Cubic Feet of air the fan pulls into the dehumidifier every Minute). We rate dehumidifiers with higher CFM fans much higher than those with lower CFM fans. Why? Because only half the battle in dehumidifying a given volume of air involves the process of actually removing moisture from it inside of the dehumidifier. The other half involves pulling that air into the dehumidifier for it to be dehumidified. A higher CFM fan is able to pull more air from greater distances surrounding the dehumidifier. This is especially important if you want to dehumidify a large space. Charts and tables don’t take into account that a smaller capacity dehumidifier with a higher CFM fan may very well outperform a larger capacity dehumidifier with a lower CFM fan under certain circumstances.
4. Charts and manufacturer recommendations are usually based on an extrapolation of test data obtained in a highly controlled environment. They’re not necessarily based on testing performed in a real world environment.
How can a dehumidifier manufacturer make the claim that their 50 pint dehumidifier can actually remove 50 pints of moisture per day? The manufacturer does so by having the unit tested under very specific conditions (65°F and 60% RH) in a highly controlled environment.
They then use this data (a 50 pints/day moisture removal rate under the given conditions) to make a square footage (area of coverage) recommendation.
But what if the room you need to dehumidify is much different that the test space? What if the room has high ceilings? What if the room has poor vs. good ventilation? What if you’re running an HVAC system in addition to the dehumidifier? What if you place the dehumidifier in your basement vs. a second story?
Charts and tables cannot account for these real world variables.
5. Another issue is that certain manufacturer recommendations contradict each other. Some manufacturers advertise their 50 pint dehumidifier as being able to cover 4,000 sq. ft. Others claim 4,500 sq. ft. of coverage. Which is it if all units are rated for 50 pints/day of moisture removal?
6. Finally, charts and manufacturer recommendations contradict our own research and testing. Take for example, many manufacturers recommending a 22 pint unit for spaces up to 1,500 sq. ft. Our own research and testing has shown that a 22 pint dehumidifier is not at all capable of properly dehumidifying a space as large as 1,500 sq. ft.
Our Recommendation – Dehumidifier buyers guide
Clearly, we believe that dehumidifier sizing charts and tables have a lot of flaws. And, because of those flaws, it is our strong recommendation that you do NOT use these charts and tables to determine what size dehumidifier you should buy.
So, what do we recommend? Our recommendation is simply the following:
Buy the highest capacity dehumidifier you can afford.
In other words, we recommend that you buy a 50 pint dehumidifier – the highest capacity consumer-grade dehumidifier you can buy.
If you have a smaller space or a space that’s not very damp – say you live in an approximately 1,000 square foot apartment and/or a space that rarely gets above 60% RH – then you certainly can get away with a medium (35 pint) or low (22 pint) capacity unit. But, you’ll be doing so at a cost. What exactly is that cost? We explain below.
Why You Shouldn’t Take Our Recommendation Lightly
Our recommendation that you buy the highest capacity dehumidifier you can afford (for consumers this means 50 pint) is based on the following very simple fact:
High capacity 50 pint dehumidifiers dehumidify faster than lower capacity 35 and 22 pint units.
It may sound like we’re stating the obvious here but really think about that statement – a high capacity 50 pint dehumidifier dehumidifies faster.
It’s easy to associate a 50 pint dehumidifier’s actual capacity with a certain volume of water – the volume of water that the dehumidifier removes from the air each day. And the truth is that such an association isn’t incorrect. A 50 pint dehumidifier is certainly capable of removing a volume of 50 pints of water from humid air every day.
But, the much more important association to make here is that a dehumidifier’s capacity relates to the rate at which it can remove moisture. A 50 pint dehumidifier removes any given quantity of moisture – not just 50 pints – at a faster rate in any given quantity of time – not just in 24 hours.
If this sounds confusing, think about it this way. A 50 pint dehumidifier is rated to remove 50 pints of moisture per day. This translates to 2.1 pints of moisture removal per hour. A 35 pint dehumidifier can remove 1.5 pints of moisture per hour and a 22 pint dehumidifier can remove 0.9 pints per hour. Let’s say you have a space that holds a block of air containing 100 pints of moisture. Here’s how fast each size/capacity dehumidifier will be able to remove that moisture:
50 pint – 48 hours
35 pint – 66.7 hours
22 pint – 111.1 hours
Clearly, given a set quantity of moisture, a 50 pint dehumidifier can remove that moisture much faster than 35 or 22 pint dehumidifier.
Another way of looking at it is with percentages.
In order to remove any given quantity of moisture from any given space, a 50 pint dehumidifier, compared to a 35 pint dehumidifier, will be able to remove that moisture 40% faster. Compared to a 22 pint dehumidifier? A whopping 133% faster!
Because it dehumidifies faster, a 50 pint dehumidifier needs to run for a much shorter period of time than smaller capacity dehumidifiers to dehumidify any size space under any conditions.
This is extremely important for the following reasons, which also happen to be the primary reasons why we feel so strongly about recommending 50 pint units:
1. It makes 50 pint dehumidifiers more energy efficient compared to smaller capacity units. 50 pint dehumidifiers do draw more power than smaller capacity units per unit time but they draw this power over a much shorter period of time. We’ve done the math and the end result is that, in real-world conditions, 50 pint dehumidifiers are, overall, more energy efficient than smaller capacity dehumidifiers over time. You should be able to more than recoup the initial cost difference between a 50 pint and a 35 or 22 pint dehumidifier in energy cost savings over time.
2. It makes 50 pint dehumidifiers more reliable than smaller capacity units. This is perhaps the biggest reason why we recommend 50 pint units. You see, every minute that your dehumidifier runs puts stress on its internal parts (its compressor, condenser, etc.). Because 50 pint dehumidifiers have to run for a shorter amount of time than smaller capacity units to dehumidify any given quantity of air, the stress on their internal parts occurs over a much shorter amount of time. This allows them to last much longer than smaller capacity units.
Think of it this way: a dehumidifier’s longevity isn’t determined by how long you own it but rather by how many hours you operate it. The math is simple. A smaller capacity unit has to operate for a far greater number of hours than a large capacity unit to dehumidify the same space with the same amount of moisture.
We’ve surveyed countless consumer reviews for hundreds of different dehumidifiers of all different sizes. It’s actually startling to see how big of a discrepancy there is between the number of consumer complaints about the reliability of smaller capacity units (35 and especially 22 pint) compared to the number of those complaints for large capacity (50 pint) units. The percentage of complaints is much much higher for smaller capacity units.
How We Test Dehumidifiers – buyers guide
We test dehumidifiers in three categories based on capacity, a claimed measurement of the amount of water each model can remove from the air—a claim we test. Here’s how we categorize the models in our current dehumidifier ratings:
Small: Claimed to remove 20 to 25 pints of moisture per day.
Medium: Claimed to remove 30 to 35 pints per day.
Large: Claimed to remove 40 or more pints per day.
Our water-removal tests measure a dehumidifier’s ability to remove moisture from the air (the number of pints of water per day, as claimed by the manufacturer) in our test chamber set at 60° F and 60 percent relative humidity. The humidistat accuracy test determines how closely each dehumidifier can reach and maintain a set humidity level.
For energy efficiency, our engineers calculate the amount of energy it takes to remove 1 pint of water from the air. For our convenience rating, we evaluate how often you’ll have to empty the tank. We also measure and judge noise levels.
These lab test results, along with brand reliability and owner satisfaction data from our CR member survey, are incorporated into an Overall Score for each dehumidifier.
Here are some of the more popular brands. DeLonghi, GE, Hisense, HomeLabs, Honeywell, Keystone and Midea etc.
DeLonghi is known for its countertop appliances, along with space heaters and portable air conditioners. Its dehumidifiers come in small, medium, and large capacities. Prices range from $270 to $390, and you’ll see the humidifiers at Lowe’s, Amazon, and other online retailers.
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