What Size Dehumidifier Do You Need?

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Getting a dehumidifier that is too large or powerful for your space can mean a lot of wasted money upfront and high electricity costs. But getting one that is too small will leave you suffering in hot, humid conditions.

Unfortunately, figuring out what size dehumidifier you need for your room or home is anything but straightforward.

That’s why we put together this helpful article. Below, you’ll find everything you need to understand how dehumidifiers are sized, what factors need to be considered to find the right size for you, and answers to all your other dehumidifier sizing questions.

hOmeLabs dehumidifiers on the floor

A Quick Dehumidifier Size Chart

Use the chart below to quickly get a quick idea as to what size dehumidifier you need.

Conditions300 sq ft500 sq ft800 sq ft1200 sq ft
Under 60% humidity20 pint25 pint35 pint50 pint
60% – 70% humidity20 pint30 pint40 pint50 pint
70% – 80% humidity30 pint35 pint45 pint55 pint
Over 80% humidity35 pint40 pint50 pint60 pint

Understanding Dehumidifier Specifications

If you’ve already started shopping for dehumidifiers, you’ve probably noticed how many different specifications there are for these appliances. Understanding which rating tells you what will help you find the right size dehumidifier to fit your needs.

Dehumidifier Sizing Standards

dehumidifier specification guide

The two most common dehumidifier ratings are pint capacity and room size coverage. You may also see the reservoir size listed. And, of course, you’ll need to take the physical measurements of the unit into account as well.

Pint Capacity

Of all the numbers associated with a dehumidifier, pint capacity is arguably the most informative. But, it can also be one of the most confusing.

Note: The pint rating does not tell you how much water the unit can hold. Rather, this number is a measurement of the appliance’s power. 

In other words, it tells you how quickly and efficiently it can remove humidity from the air.

The manufacturer calculates the pint capacity using a standardized test wherein the unit is placed in a room with 60% humidity at 65 degrees. The pint rating reflects how much moisture was removed from the air under those conditions in 24 hours.

A 70-pint dehumidifier, therefore, is more powerful than a 50-pint dehumidifier. The physical size of the units and the reservoir capacity has nothing to do with the overall pint rating.

To better understand how this works, check out our article on how dehumidifiers function.

It is worth noting that the standardized conditions for measuring pint capacity were updated in 2020. Before then, pint capacity was measured in a 60-degree room with 80% humidity. Because higher humidity levels make it easier for dehumidifiers to pull moisture from the air, the old standard produced higher pint ratings than the new.

When shopping for your dehumidifier, look for the updated standard as this better reflects real-world operation.

Room Size

a dehumidifier in the living room

The marketing material for most dehumidifiers will include a room size rating along with the pint rating or in place of it. This rating is loosely based on pint capacity but is often overinflated compared to common real-world conditions.

Note: Room size is not a great gauge for measuring the power of a dehumidifier because different humidity levels and temperatures require different power ratings. This is true, even if the size of the room remains consistent.

For instance, a 20-pint dehumidifier is adequate for use in a 300 square foot room only so long as the humidity levels are below 70%. For higher humidity levels in a 300 square foot room, you’d need a 25 or 30-pint dehumidifier to reduce the moisture level effectively.

Because there is no standard for how room size ratings are calculated for these machines, you’ll see an impressive amount of variability in this number. One quick Amazon search for 30-pint dehumidifiers brings up units rated for room sizes anywhere between 700 square feet and 2,000 square feet.

In actuality, given the standard conditions of 65 degrees and 60% humidity, a 30-pint dehumidifier is only adequate for room sizes around 500 square feet.

We’ve included a chart in the next section to help you better understand how pint capacity translates to use in different sized rooms based on the conditions. Your best bet is to ignore the marketed room size rating and reference this table instead.

Reservoir Size

reservoir of a 50-pint dehumidifier

The size of your dehumidifier’s reservoir is another size rating worth looking at. This feature won’t affect how powerful the unit is, but it can reduce its dehumidifying capacity since the unit will automatically stop dehumidifying when the reservoir fills up.

Units with small reservoirs will need to be dumped more frequently than those with larger reservoirs. Dehumidifiers with hose hookups and/or pumps can be set up to automatically drain through a floor drain, into a sink, or out a window. If you plan to use this feature, the size of the reservoir won’t matter.

Physical Measurements

small portable dehumidifiers on the floor

The physical measurements of a dehumidifier don’t strictly determine the unit’s power rating. But, of course, those with higher pint ratings do tend to be larger than those with smaller ratings.

Personal dehumidifiers are typically made for tiny spaces such as bathrooms and small bedrooms. The power rating of these units is usually given in ounces rather than pints because their capacities are so much lower than standard units. These compact appliances are small enough to fit on your bathroom counter or dresser.

Once you get into units 20 pints and up, you’ll find the dehumidifiers themselves are all around the same size. These are large enough to place on the floor and often come with casters so you can move them around easily.

Note: If you are looking to dehumidify a small space, you have the option to get an undersized dehumidifier. In all other cases, you’ll be looking at appliances around 19 to 25 inches tall, regardless of the pint capacity rating.

Important Factors for Deciding the Size of Your Dehumidifier

a small portable dehumidifier on the windowsill

As you can see from the information above, there is a lot more that goes into determining the size of your optimal dehumidifier than just how big the room is. Here are four things you need to consider before you can find the right size unit for your needs.

Humidity Levels

dehumidifier capacity chart

How humid your room or home is plays a huge role in how powerful your dehumidifier will need to be

Note: Very humid basements require more consistent moisture removal than a bedroom of the same size that is already near comfortable humidity levels.

If you haven’t already, it is worth purchasing a hygrometer to measure your home’s humidity levels. Watch how this number changes throughout the day, paying special attention to the levels during those noticeably uncomfortable periods. Use the highest readings and the chart above to help you determine the pint capacity your new dehumidifier will need.

Size of the Area

The second most important factor to consider is where you will be using your dehumidifier and how big that space is. 

Dehumidifiers for bedrooms over 100 square feet will likely need a standard dehumidifier rather than a personal portable unit. 

Note: The larger the bedroom, the higher pint capacity you’ll need. On the other hand, if you have a small room, bigger isn’t going to be better. 

While high capacity units will lower the humidity levels in a small room faster, they’ll also draw more power. These big units also tend to put out more noise that can be especially noticeable in a small space. Small rooms will benefit from ultra-quiet dehumidifiers.

Rather than going for the biggest unit you can find, opt for the optimally sized model for your room based on square footage and humidity conditions.

Temperature of the Area

a person holding a hygrometer

Another consideration to take into account is the average temperature of the room. The chart above is based on rooms at temperatures of 65 degrees. For your typical room, you can choose the correct size dehumidifier straight from this chart.

But if you are shopping for an especially cool basement or hot loft, the parameters change.

Dehumidifiers are more effective at removing moisture at high temperatures than at low ones. So, while you’d need a 50-pint dehumidifier in a 65 degree, 800 square foot room, you could get away with a 40-pint unit if that same room averaged around 80 degrees.

The opposite is true of cold rooms. You’ll want to opt for a unit that is about 10-pints larger than what’s recommended on the chart above for rooms that stay below 60 degrees.

Cost To Run

Another thing worth considering before going all-in on a new dehumidifier is how much the unit will cost to run. 

We already discussed that choosing a unit more powerful than you need is a bad idea because it will cost more to run. The same can be true of choosing a smaller unit than you need.

Note: Smaller units may draw less power per minute, but they’ll also need to run longer than more powerful units to bring humidity levels down. Your minute-to-minute costs will be less, but your overall cost to run will be higher. 

To optimize your power costs, choose a unit best suited for your room size and conditions. Even within products optimized for your needs, you’ll find differences in operating costs.

Energy Star Rated appliances like our favorite hOmeLabs dehumidifier are a better choice than those without any energy certifications. Many units also come with energy-saving features such as timers, target level mode, and energy saver mode.


What Size Dehumidifier Do I Need for a Basement?

Dehumidifiers for basements can be chosen using roughly the same criteria as dehumidifiers for other rooms. Start by measuring your average humidity levels and the basement’s square footage and use our chart above to calculate the optimally sized dehumidifier for the space.

For large basements, it is also worth considering whether or not the space is finished. The chart below gives the recommended pint capacity rating for different sized basements based on how well they are sealed. This chart assumes a high humidity rating of over 70%.

Sealing Status2,000 square feet3,000 square feet4,000 square feet
Loosely sealed90 pints110 pints150 pints
Moderately sealed80 pints95 pints125 pints
Tightly sealed70 pints80 pints100 pints

What Size Dehumidifier Do I Need for a 500 Sq Ft Room?

A 500 square foot room under average conditions (60% humidity and 65 degrees) will need a 30-pint dehumidifier. However, humidity levels and temperature changes will affect which unit is optimal for that size room.

High humidity requires a higher capacity unit, while lower humidity rooms can get by with a less powerful dehumidifier. Similarly, colder rooms require a more powerful dehumidifier, while warmer rooms need a less powerful one.

What Size Dehumidifier for a 1000 Square Feet Area?

A 1000 square foot room under average conditions (60% humidity and 65 degrees) will need a 45-pint dehumidifier. But, again, this recommendation changes if the humidity level and temperature are outside the typical range. 

A more humid 1,000 square foot room will be better off with a 50 or 60-pint unit. Similarly, a cooler room will need a more powerful unit to extract moisture from cold air efficiently. If the area is a basement, then how well sealed it is will also play into how powerful the dehumidifier needs to be.

Can I Use Multiple Dehumidifiers at Once?

Because most quality dehumidifiers can be set to turn off once the target humidity level is achieved, running two units simultaneously shouldn’t technically cause any issues. However, in terms of cost, you may not want to go this route.

A single dehumidifier optimized for the room size you are using it in will be more cost-effective upfront and in how much energy it uses than running two units rated for half that room size.

Now, when it comes to dehumidifying two separate rooms, two is likely better than one. If the rooms are a good distance apart, you are better off getting two units rated for each room size rather than getting one unit rated for the shared area.

Wondering how else you can optimize your dehumidifier use? Check out our article, How to Use a Dehumidifier, for more tips and tricks.

Can a Dehumidifier Be Too Big?

Yes, a dehumidifier can be too big, both for your needs and your space.

As I mentioned above, most dehumidifiers allow you to set your target humidity level and will turn off once it is achieved. Because of this, some people think that a bigger unit is better because it can reach this set point more quickly than a smaller unit.

But these more powerful units cost a lot more upfront and cost significantly more to run. Additionally, units rated over 20 pints take up significantly more room than personal-use units. For tiny rooms, this can be problematic.

Instead, it is best to choose a unit optimized for the size and conditions of the room you will use it in. This will ensure you don’t spend too much upfront and that your monthly costs are where they should be to keep you comfortable.

What Does a 70 Pint Dehumidifier Mean?

The pint rating of a dehumidifier refers to the amount of moisture the unit can remove from a 65-degree room at 60% humidity over 24 hours. A 70-pint dehumidifier can remove 70 pints of moisture from a room in these conditions in one 24 hour period.

The pint capacity rating is a measure of the unit’s power. It is not directly determined by the unit’s physical size and has nothing to do with the capacity of the water reservoir.

At 65 degrees and 60% humidity, a 70-pint dehumidifier is optimal for a 1,500 square foot space. However, in more humid conditions, a 70-pint unit is better suited to a smaller space. In less humid conditions, it can cover a larger area.


An optimally-sized dehumidifier can help save money while keeping your home more comfortable. But figuring out the right size unit for your needs requires considering multiple factors.

First, you need to know the size of the room you will be using it in and the average humidity level of that room. Next, you need to take into account the average temperature of the room, how much space you have available to dedicate to the unit, and how much you can afford to add to your energy bills each month.

By considering these factors as you shop for your new dehumidifier, you can be sure you’ll end up with a unit that is exactly the right size for your needs and space.

Have special circumstances that we didn’t cover above or other questions concerning dehumidifier sizing? Comment below and we’ll be happy to help.

Do you have any questions relating to this article? Email us at e[email protected] or call us on +1 (310) 961-4908

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Aaron is the founder of and Essential Home and Garden. With over 15 years of hands-on experience in home ownership, lawn care, and gardening, Aaron is a seasoned expert in areas like lawn care, DIY, HVAC, and pest control.

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