What Size Dehumidifier Do I Need
This post was last updated on: October 1, 2021

Humid air can cause problems for people living in humid areas. You may notice mold, mildew or a musty smell. Your home and furniture may be more susceptible to damage from water damage.

The humidity itself is bad for your health as the higher levels of moisture in the air can lead to sinus infections, allergies and asthma.

Maintaining low humidity levels is essential to keep your home comfortable and safe from these issues.

This article will help you determine what size dehumidifier you need based on square footage so you can maintain a healthy level of indoor air quality with minimal effort!

The amount of moisture a dehumidifier can remove from the air per day is mainly determined by the relative humidity, total square feet of the room, and the average temperature.

Other factors such as machine type and machine placement in relation to air flow may also affect how much water was extracted.

If you also run your air conditioner all the time, or have a solid HVAC system, you also might not need as large of a model.

1. Estimate the relative humidity

Unless you have a Mathematics degree, it’s probably easiest to guesstimate the relative humidity of your house or room. Just ask yourself if the air feels slightly damp, moderately damp, very damp, or wet.

A slightly damp space might smell damp (50-60% humidity). At moderately damp, you’ll definitely smell the mustiness (60-70% humidity). At very damp, you may even see damp spots appear on the walls or flooring (70-85% humidity). At wet, you’ll see the wet spots and may even see mold growth (85-100%).

If you live in an area of high humidity, you might consistently hit the very damp or wet mark, in which case you’d really need a large capacity unit.

2. Measure the square footage of a room

1. Measure the length and width of the room with a tape measure

2. Multiply these measurements to get the total square footage

3. Repeat the above two steps and add the totals together to get the square footage of your whole house

3. Estimate the average temperature

The ideal operating temperature for refrigerant dehumidifiers is between 70 and 90 degrees F. This range ensures that they are able to produce a large enough volume of condensation while remaining below the boiling point so as not to damage other parts or lose their cooling capacity.

Quick and Easy Dehumidifier Size Chart

Environment 300 square feet 500 square feet 1000 square feet 1500 square feet
Slightly Damp
30 pint
45 pint
60 pint
70 pint
Moderately Damp
30 pint
45 pint
60 pint
70 pint
Very Damp
40 pint
50 pint
70 pint
90 pint
Wet
45 pint
60 pint
75 pint
90+ pint

Frequently Asked Questions

How often will you have to empty your water bucket or drain tube?

The answer depends on how humid the air is in your home, and what type of unit you are using.

For an average residential setting with low humidity levels, we recommend checking for water once every two weeks or so depending on whether it has rained recently outside which can cause excess moisture inside as well!

Do I need an electrical outlet close by for my dehumidifier?

The answer is yes. A dehumidifier needs to be plugged in in order to run, so having an electrical outlet near wherever you place the unit is a must. Unless you use an extension cord, of course.

Do I need to get an energy efficient dehumidifier, or will any type of machine work for me?

There are three main types of dehumidifiers: evaporative dehumidifiers, desiccant dehumidifiers, and compressor dehumidifiers. They all work by removing the water from the air to reduce humidity levels but each type achieves this task in a different way.

For instance, a desiccant dehumidifier relies on natural chemical reactions and evaporative dehumidifiers use an evaporation process to remove water from the air. Compressor models use mechanical force to compress air that has already had most of its moisture removed.

We recommend always going after models that have better energy efficiency in order to save energy or spending more money than you need to.

Related: Most Energy Efficient Dehumidifiers

Should I buy a whole house dehumidifier or just a portable one that can be moved around as needed?

There are a number of factors to consider.

How large is the space you wish to dehumidify? If the room size is less than, say 500 square feet, then portable models will do the job and save on energy costs. Larger spaces may benefit from whole house dehumidifiers, because they can extract moisture for hours before it needs to be drained or switched off.

If there are areas with less than 500 square feet that have high humidity, then you might be better off purchasing a portable dehumidifier for that specific area.

Related: Best Whole House Dehumidifier

What size dehumidifier do I need for a basement?

It really depends on how much water your basement collects. We suggest measuring the size of the space (in square feet) and then turning on your appliance to see how many pints an hour it removes.

It’s best to get a slightly larger model than you need that can absorb any extra you run into later instead of being short-sighted and picking up an expensive smaller one now.

This is especially true if you live somewhere that has a particularly humid climate, or if your basement area tends to be an extremely wet space.

Related: Best Basement Dehumdifier

What size dehumidifier do I need for 1000 square feet?

The first and most important factor to consider is the relative humidity in the home.

For 1000 square feet of space that hovers around 30%-50% RH, a 50 pint dehumidifier might be appropriate. However, for a very damp space with a high moisture level, you may need upwards of a 70 pint dehumidifier to prevent mold growth.

Is it better to get a bigger dehumidifier?

In most cases, the answer to this would be no. If you’ve correctly calculated everything above, you should have enough information to purchase the right dehumidifier for your space.

Anything above and beyond that would be detrimental to the overall energy efficiency of your home.

How many square feet does a 50 pint dehumidifier cover?

Once again, the most important factor to consider is the relative humidity of the area. Generally speaking, a 50 pint dehumidifier should safely cover approximately 750 square feet. The caveat to this is if there are extremely wet spaces or an overtly high moisture level. If your room has musty odors, assume a larger size dehumidifier is needed.

How many square feet does a 20 pint dehumidifier cover?

Similar to the above, it all comes down to the relative humidity. But a 20 pint dehumidifier should be enough for approximately 150 square feet of space.

In Closing

Based on the above, you can now estimate how much moisture a dehumidifier can remove from the air per day.

In short, a good unit will extract around 2-5 gallons per day, but for higher capacity units you could expect to get up to 13 gallons in a 24 hour period at 85% relative humidity and 86 degrees Fahrenheit.