Last Updated: April 5th 2018
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 upwards of 10 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 not going to talk about them in this guide (for information on these dehumidifiers see our thermo-electric and desiccant dehumidifier guides).
Instead, our focus in 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 Before You Buy
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 a very important concept – dehumidifier capacity.
A clear understanding of this concept will be absolutely critical for you to determine exactly which model dehumidifier you need to buy.
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.
We mentioned earlier that compressor based dehumidifiers are capable of removing upwards of 10 gallons of water from the air per day. But not all of them can remove a whole 10 gallons. Some can only remove about 6 gallons per day, others only 4 gallons per day.
How much water (moisture) a dehumidifier can remove from the air per day is referred to as the dehumidifier’s capacity. So, a dehumidifier that can remove 10 gallons of water from the air per day is said to have a capacity of 10 gallons. Or is it?
Dehumidifier manufacturers 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, the dehumidifiers we talked about having a capacity of up to 10 gallons per day are simply referred to as 70 pint dehumidifiers. 70 pints is actually a little bit less than 10 gallons. It’s equal to 8.75 gallons to be exact.
70 pint dehumidifiers are the most common type of compressor based dehumidifier, followed by 50 pint dehumidifiers (50 pints = 6.25 gallons) and 30 pint dehumidifiers (30 pints = 3.75 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 32, 45, or 65 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 would point you to a size chart to help you determine what capacity dehumidifier you need to buy. The most popular of such sizing charts is the one given by AHAM, the Association of Home Appliance Manufacturers. AHAM tests and verifies the moisture removal rate and energy efficiency of most dehumidifiers sold in the United States (note that they don’t actually review and compare dehumidifiers; they just verify manufacturer claims). Because they conduct this testing and verification they’re viewed as an authority on dehumidifiers. And so, most consumer publications reference their size chart without hesitation. The AHAM chart we’re talking about is reproduced in the table below.
To use this chart follow these steps
- 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
For example, let’s say you have a very damp 1,000 square foot space – the chart advises that you buy a 17 pint dehumidifier.
Area (Sq. Feet)
Furthermore, the chart makes the following definitions:
- Moderately Damp: space feels damp and has musty odor only in humid weather
- Very Damp: space always feels damp and has musty odor. Damp spots show on walls and floor.)
- Wet: space feels and smells wet. Walls or floor sweat, or seepage is present.)
- Extremely Wet: laundry drying, wet floor, high load conditions.)
Unlike most other consumer publications, we do not recommend that you use the chart above to help you decide what capacity dehumidifier to buy.
Why do we disagree with the use of this chart? See the 8 reasons below.
1. The chart cannot actually be found anywhere on AHAM’s official website or AHAM’s official test specification website. Even though a number of different consumer publications reference the chart above and give the source as AHAM, the fact that AHAM is indeed the source cannot be verified because the chart, as it has been reproduced by those same publications, doesn’t actually exist anywhere on any of AHAM’s websites.
Update: A reader recently informed us that the chart does in fact exist on AHAM’s website. The chart can be found at the bottom of this PDF file. While the existence of this chart on AHAM’s website does eliminate this first reason for our disagreeing with its use, it certainly doesn’t eliminate the 7 other reasons listed below. Read on to find out why we still do not recommend using AHAM’s official sizing chart.
2. Only two of the capacities listed in the chart – 32 in the second and third row and 30 in the bottom row – correspond to actual capacities of dehumidifiers you can buy in stores. Reading the top row of the table, there are no 10, 14, 18, 22, or 26 pint dehumidifiers readily available for purchase anywhere online or in stores.
3. The chart has a limited range. It begins at 500 square feet and ends at 2500 square feet. What if the space you need to dehumidify is smaller than 500 square feet? What if it’s larger than 2500 square feet? The chart fails to make recommendations for spaces that fall outside of the given range.
4. The chart fails 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 the chart above 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.
5. The chart fails 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. The chart above doesn’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.
6. The chart is likely based on an extrapolation of test data obtained in a highly controlled environment. It’s likely not based on actual experiments in environments corresponding to the actual conditions (moderately damp, very damp, wet, extremely wet) it makes recommendations for.
How can a dehumidifier manufacturer make the claim that their 70 pint dehumidifier can actually remove 70 pints of moisture per day? The manufacturer does so by voluntarily sending it to AHAM for testing. AHAM then measures the dehumidifier’s moisture removal rate in a laboratory that is set to exactly 60% relative humidity (RH) and 80º F.
We think it’s safe to assume that AHAM doesn’t actually conduct any testing in the “wet” or “extremely wet” conditions referenced in their sizing chart. It’s highly unlikely, for example, that they conducted testing in a room with wall or floor sweat (a room that would be classified as “wet” in the chart) or in one in which laundry drying occurs (a room that would be classified as “extremely wet” in the chart). The bottom-line here is that the chart is likely based on data obtained in a space much different than the space that you actually need to dehumidify.
7. The chart contradicts manufacturer recommendations. See this Friedrich dehumidifier brochure, for example. It recommends that a 70 pint dehumidifier be used for a 1,000 to 2,000 sq. ft. “wet” or “extremely wet” space which contradicts the 20 pint to 37 pint recommendation of the size chart above for the same size space under exactly the same conditions.
8. The chart contradicts our own research and testing. Take for example, the chart’s recommendation that a 44 pint dehumidifier be used for a 2,500 sq. ft. “extremely wet” space. Our own experiences with all of the dehumidifiers we’ve tested so far lead us to believe that a 44 pint dehumidifier (which doesn’t actually exist, but that’s beside the point here) is not nearly of a large enough capacity to dehumidify such a large space under those conditions.
Clearly, we believe that the AHAM dehumidifier sizing chart has a lot of flaws. And, because of them, it is our strong recommendation that you do not use it to determine what size dehumidifier you should buy. So, what do we recommend? Our recommendation is simply the following:
Buy the largest capacity dehumidifier you can afford.
In other words, we recommend that you buy a 70 pint dehumidifier – the largest capacity consumer-grade dehumidifier you can buy – regardless of the size or dampness of the space you need to dehumidify.
If you have a smaller space that’s not very damp – say you live in an approximately 1,000 square foot apartment – then you certainly can get away with a 50 pint or even a 30 pint 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 largest capacity (for consumers this means 70 pint) dehumidifier you can afford is based on the following very simple fact:
70 pint dehumidifiers dehumidify faster than 50 or 30 pint units.
It may sound like we’re stating the obvious here but really think about that statement – a 70 pint dehumidifier dehumidifies faster.
It’s easy to associate a 70 pint dehumidifier’s 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 70 pint dehumidifier is certainly capable of removing a volume of 70 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 70 pint dehumidifier removes any given quantity of moisture – not just 70 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 70 pint dehumidifier is rated to remove 70 pints of moisture per day. This translates to 2.92 pints of moisture removal per hour. A 50 pint dehumidifier can remove 2.08 pints of moisture per hour and a 30 pint dehumidifier can remove exactly 1.25 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.
70 pint – 34.25 hours
50 pint – 48.08 hours
30 pint – 80 hours
Clearly, given a set quantity of moisture, a 70 pint dehumidifier can remove that moisture much faster than smaller capacity dehumidifiers.
Another way of looking at it is with percentages.
In order to remove any given quantity of moisture from any given space, a 70 pint dehumidifier, compared to a 50 pint dehumidifier, will be able to remove that moisture 40% faster. Compared to a 30 pint dehumidifier? A whopping 134% faster!
Because it dehumidifies faster, a 70 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 70 pint units:
1. It makes 70 pint dehumidifiers more energy efficient compared to smaller capacity units. 70 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, 70 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 70 pint and a 50 or 30 pint dehumidifier in energy cost savings over time.
2. It makes 70 pint dehumidifiers more reliable than smaller capacity units. This is perhaps the biggest reason why we recommend 70 pint units. You see, every minute that your dehumidifier runs puts stress on its internal parts (its compressor, condenser, etc.). Because 70 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 (50 and especially 30 pint) compared to the number of those complaints for large capacity (70 pint) units. The percentage of complaints is much much higher for smaller capacity units.
Our Top Picks for 2018
After several hundred hours of research, testing, and in-depth analysis here are our model recommendations for 2018. These are the very best dehumidifiers we’ve tested so far.
Best Rated Overall – Frigidaire FFAD7033R1
Simply put, the Frigidaire FFAD7033R1 is by far the best dehumidifier we’ve tested as of the writing of this guide in early 2018. It is unequivocally the best dehumidifier on the market today. Here’s why.
It removes moisture fast – We conduct two different tests to determine how well and how fast a dehumidifier can remove moisture in a real-world environment. In the first test we measure how long it takes for the dehumidifier to lower room humidity from 90% down to 40% relative humidity (RH). In the second test we measure how long it takes for it to lower room humidity from 80% down to 50% RH. The FFAD7033R1 was able to lower room humidity from 80% down to 50% RH faster than any other dehumidifier we tested. It was the second fastest lowering room humidity from 90% down to 40% RH.
It’s quiet – The FFAD7033R1 has two things going for it when it comes to producing as little noise as possible. First, it doesn’t produce any audible compressor noise. Ever hear your fridge’s compressor kicking on? If you get really close to your fridge and/or if you have an older fridge you may very well be able to hear its compressor make a buzzing noise. A dehumidifier also has a compressor and it also can produce the same buzzing noise a refrigerator’s compressor can make. The FFAD7033R1′s compressor didn’t produce any audible noise during testing. The same cannot be said for many of the other dehumidifiers we tested.
The second thing the FFAD7033R1 has going for it, in terms of noise output, is the fact that it exhausts out of its side. On a dehumidifier such as this one with very little to no compressor noise, exhaust fan noise makes up all the noise you’ll hear when you turn it on. The FFAD7033R1 exhausts out of its side allowing you to direct this noise wherever you want by simply rotating the dehumidifier on its casters. Most other dehumidifiers on the market exhaust upward in which case fan noise is always directed upward as well. This type of noise distribution is much more difficult to manage.
It’s exceptionally well-built – We’ve had a lot of hours getting hands-on experience with a lot of different dehumidifiers. In terms of build quality and the quality of the materials used for its construction, the FFAD7033R1 is simply a cut above every other dehumidifier we’ve tested so far. It’s actually remarkable how big of a difference there is, in terms of build quality, when comparing the FFAD7033R1 directly side by side with other dehumidifiers. Placed directly next to other popular dehumidifiers it would be obvious even to someone with far less experience with dehumidifiers than we have, that the FFAD7033R1 is clearly a much better built higher quality appliance.
The FFAD7033R1 does more things better than any other dehumidifier we tested. It earns our highest recommendation as the best dehumidifier on the market today.
Note that 50 and 30 pint versions of this particular model are also available for purchase. Both units are identical to the 70 pint version except for capacity and size. They have exactly the same control panel, the same exhaust location, the same build quality, etc. Of course, we do not recommend those versions over the 70 pint unit, but should you be set on purchasing a smaller capacity unit you can be confident that they provide similar noise output, exactly the same build quality, and most other benefits just the same as the 70 pint unit but at a smaller capacity.
Best Budget Alternative – Keystone KSTAD70B
The Frigidaire FFAD7033R1 is by far the best dehumidifier we’ve tested so far but it’s price and availability is often such that it may be out of reach for some consumers. A more budget-friendly alternative is the Keystone KSTAD70B. Here are the reasons why the KSTAD70B is a great second option.
It’s highly energy efficient – the KSTAD70B one of the most energy efficient 70 pint dehumidifiers we tested with a measured power draw of only 590 watts.
It’s quiet – this Keystone dehumidifier is one of the most quiet dehumidifiers in its size class. We measure the noise output (in dB using a sound meter) for all of the dehumidifiers we test for review. The KSTAD70B is one of the most quiet 70 pint dehumidifiers we’ve tested so far.
It dehumidifies fast – it doesn’t dehumidify quite as fast as the Frigidaire FFAD7033R1 but it’s still faster than average in its size class (70 pint). As noted above, we measure a dehumidifier’s moisture removal rate in two different tests. The KSTAD70B didn’t perform quite as well in these tests as the FFAD7033R1, but its performance was still above average.
The Keystone KSTAD70B removes moisture faster than most other 70 pint dehumidifiers we tested but more importantly, it removes moisture much faster than any 50 pint or 30 pint dehumidifier. This is important because the KSTAD70B is often priced much less than the average 50 pint dehumidifier and only $10 or $20 more than the average 30 pint dehumidifier. If you’re torn between purchasing a 30 or 50 pint unit and this Keystone 70 pint unit, our recommendation, without hesitation, would be the Keystone.
Read our Full Review
Spring 2018 Update: It has recently come to our attention that the KSTAD70B is out of stock at most online retailers, indicating that it may have been discontinued by the manufacturer. Upon further research, it appears to have been replaced by the KSTAD70C.
Based on the fact that these two models appear to be functionally identical (they both appear to have an identical control panel and internals) and because of the “B” model’s lack of availability, we currently recommend the Keystone KSTAD70C as the best budget dehumidifier option for 2018.
Why You Can Trust Our Recommendations
So far we’ve personally tested over 50 different dehumidifiers. Many other reviewers base their recommendations on manufacturer specifications. These specifications list performance data (namely moisture removal rate and noise output) that is based on testing conducted in a highly controlled environment which maximizes the performance of the dehumidifier and allows it to get ideal results. Our tests simulate real world environments and conditions that aren’t always ideal to determine how each dehumidifier we test actually performs in real-world environments. We rigorously test each unit to determine how quickly it removes moisture, how much noise it produces, how much energy it uses, and just how accurate its built in hygrometer (used to read humidity levels) really is in a typical home environment. This means that our test data is often quite different than what manufacturer specifications indicate.
In addition to the tests described above we also take time to assess each unit’s build quality, its features, portability, adjustability, versatility, and how easy it is to use. Finally, we examine its warranty, price, and consumer feedback and compare it to the other dehumidifiers we’ve tested. This is how we determine the best dehumidifier in each category.
Our Dehumidifier Reviews
Each of our dehumidifier reviews is broken down into 13 different categories including
- Energy Efficiency
- Noise Output
- Moisture Removal Rate
- Hygrometer Accuracy
- Extra Features
- Ease of Use
We use the rating rubric below to give each dehumidifier we test a score out of 5 in each category.
|2.0||Below Average||Our worst rating indicating poor and unacceptable performance|
|3.0||Below Average||Below average but acceptable performance|
|3.5||Average||The unit's performance was up to par compared to the industry standard|
|4.0||Above Average||Only slightly above average performance|
|4.5||Above Average||More than slightly above average but also not perfect|
|5.0||Above Average||Perfect. Nothing could have been done better|
These 13 scores are then added up to give the dehumidifier a cumulative score. It is largely this cumulative score that we use to determine the best dehumidifier in each size category.
All the dehumidifiers we’ve tested so far, ranked according to their cumulative score (in the right-most column), are listed in the tables below. Note that you can read our full review for each unit by clicking on its model name.
70 Pint Dehumidifiers
50 Pint Dehumidifiers
30 Pint Dehumidifiers