What Size Dehumidifier Do I Need – Consider These Factors

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What Size Dehumidifier Do I Need

A dehumidifier comes in various sizes and dehumidifying capacities to attend to varying humidity levels and room sizes—for example, bedroom, basement, garage, etc. Thus, there’s no “one size fits all” here. 

You’ve to consider many factors to determine your dehumidifier’s perfect size. This will help you spend wisely and be mindful of your monthly energy bill. And most importantly, it will keep uncomfortable humidity at bay!

Read on, as this blog post will help you gauge the ideal dehumidifier size, with particular emphasis on the bedroom and basement. 

Note: Remember to save the dehumidifier sizing chart for future reference.  

Related: Air Purifier vs. Dehumidifier – Key Differences & Types

Does Size Matter for Dehumidifiers?

Yes, it does. 

As you know, a dehumidifier’s primary function is to remove excess water vapor from the air to control humidity. And the size has a significant say if you talk about its water vapor-sucking capacity. 

Note: A dehumidifier’s capacity to remove water vapor is usually measured in pints per 24 hours

Consider this example. 

If your space measures 500 square feet, a dehumidifier with a capacity of a mere 15 pints won’t do anything.  This is because its capacity is too less for the space it’s employed for (forget the humidity levels for a second here.)

Similarly, suppose you turn on a 30-pint capacity dehumidifier in a 500 square feet space. In that case, it’ll lead to a situation of “low humidity” as your device will suck excessive water vapor from the air, which is, again, not what you’d want. 

Humidity, low or high, isn’t suitable for anyone (including plants.) While extremely low humidity triggers dry skin and roughness, high humidity results in dampness all over the space and helps molds and dust mites breed. 

Note: High humidity is also a common reason for adverse health conditions, for example, coughing, shortness of breath, and even asthma.  

Related: What Should I Set My Dehumidifier At? Answer By Room & Humidity Level

Can Your Dehumidifier Be Too Big?

Yes, the dehumidifier can be too big, provided the space is at least 1,200-1,500 square feet (or even more) and the humidity is in excess of 70%. 

If the above conditions are unfulfilled, here are the two outcomes. 

  • A large dehumidifier will take up unnecessary floor space if the space isn’t too ample. 
  • A large dehumidifier will dry the air excessively if the humidity level isn’t too high. 

Remember, the primary purpose behind using a humidifier/dehumidifier is to maintain the optimum 30-50% humidity levels. 

So, a big dehumidifier isn’t always the case. 

Then, what size dehumidifier do I need? I’ve answered this next. 

Related: Humidifier vs. Dehumidifier: What’s The Difference? (Updated!)

What Size Dehumidifier Do I Need – Know The Factors First

Here are the three main factors to know what size dehumidifier you need: easy on your energy bills and tough on humidity. 

  • The total surface area of the target room/space (e.g., bedroom, basement, indoor garden room, etc.)
  • Relative humidity (RH)
  • The average temperature of the area/space

Below is a detailed discussion of each of these factors. 

  • Total Area Of The Target Room/Space

Just like the total area of the target room is necessary if you wish to install a TV or air conditioner, the same is true for a dehumidifier. 

Now, you can take a rough assumption of the area. But I recommend gauging it using a measuring tape. 

Formula To Calculate Square Footage: Length x Width

For example, if the length comes out to be roughly 11 feet and the width is 10 feet. The room’s square footage will be 11 x 10 = 110 square feet (or ft²).

Once measured, round off the figure as an approximate number is good enough to proceed. 

Tip: For irregular rooms, calculate the area of each main section and add it to get the total area.

Related: Dehumidifier Not Collecting Water – Reasons and Solutions

  • Relative humidity (RH)

After the area, the next (and most important) thing to consider is the relative humidity (RH) levels. This parameter will determine the capacity of your dehumidifier. 

A medium-sized machine will do the job if the indoor dampness is moderate. If not, you’ll require a big machine to control high dampness. 

Again, I recommend using a hygrometer to measure the humidity levels instead of relying on what you are currently feeling. 

  • Average Temperature Of The Area/Space

I don’t know why most buyers overlook the area’s temperature while buying their dehumidifier. But it would help if you didn’t do this. 

A dehumidifier’s effectiveness in sucking extra water vapor from the air depends on the temperature of the surroundings. 

Consider this. 

  • Higher temperatures enhance the effectiveness of dehumidifiers. 
  • Lower temperatures limit the efficacy of dehumidifiers. 
  • Similarly, a big dehumidifier is the best choice to dehumidify a cold area, and vice-versa. 

Now you know why the target area/space temperature is essential.  

Dehumidifier Size Calculation – According To The Two Standards

If you didn’t know, the Department Of Energy (DOE) sets out dehumidifier sizing standards to narrow your research and efforts. 

Currently, two standards play an essential role in the size. These are:

  • Old Standard From 2012-2019: This is based on the energy factor and test temperature of 80°F. 
  • New Standard From 2020 Onwards: This is based on the integrated energy factor and test temperature of 65°F.

Since there’s no clarity on which standard is the best, the back label of the dehumidifiers displays both of these standards for your convenience. 

Here’s an example. 

50 Pint 2019 DOE (Previously 70 Pint)

Here, the dehumidifying capacity of the concerned dehumidifier is 50 pints according to the new standard and 70 pints according to the old standard. 

Dehumidifier Size Calculator – Tabular Representation

The following is the tabular representation of the size of a dehumidifier.  

Humidity Levels/Surface Area 300 Square Feet 500 Square Feet 800 Square Feet 1,200 Square Feet 1,500 Square Feet
50%-60% 30 Pint (O)

20 Pint (N)

45 Pint (O)

30 Pint (N)

60 Pint (O)

40 Pint (N)

70 Pint (O)

50 Pint (N)

80 Pint (O)

60 Pint (N)

60%-70% 30 Pint (O)

20 Pint (N)

45 Pint (O)

30 Pint (N)

60 Pint (O)

40 Pint (N)

70 Pint (O)

50 Pint (N)

80 Pint (O)

60 Pint (N)

70%-80% 45 Pint (O)

25 Pint (N)

50 Pint (O)

30 Pint (N)

65 Pint (O)

45 Pint (N)

80 Pint (O)

55 Pint (N)

80 Pint (O)

60 Pint (N)

80%-90% (or 100%) 45 Pint (O)

30 Pint (N)

60 Pint (O)

40 Pint (N)

70 Pint (O)

50 Pint (N)

90 Pint (O)

60 Pint (N)

90 Pint (O)

70 Pint (N)

Here, (O) and (N) are the Old Standard and New Standard, respectively. 

In a nutshell, as the humidity levels and the area increase, the dehumidifier’s size increases in conjunction. 

To read this table, check this example. 

If your area measures approximately 800 square feet and the humidity is roughly 60%, according to the above table, a 60-pint dehumidifier is a suitable size for you according to the old standard. 

If you go by the new standard, it’s 40 pints. 

What Size Dehumidifier Do I Need For A Bedroom?

The process of choosing the dehumidifier size for a bedroom is relatively easy. You can refer to the above tabular representation or size chart. 

Once you’ve found your bedroom size, measure the humidity levels using the hygrometer. Use these calculations for the perfect dehumidifier size, and you’re ready to go. 

Note: Besides the bedroom’s size, be mindful of your room’s crampedness. After all, you wouldn’t want an already cramped room to have to make space for a big dehumidifier (even if required.)

What Size Dehumidifier Do I Need For A Basement?

When choosing a dehumidifier for a basement, remember that such spaces usually have high humidity due to closed windows and doors. And no direct sunlight source!

That’s why you’ve to consider how sealed the basement is for basements. That is, loosely sealed, moderately sealed, or tightly sealed. 

Based on these and, of course, the total basement area, calculate the ideal dehumidifier size.

Refer to this table for more information. 

Level Of Seal/Basement Area 1,500-2,000 Square Feet 2,000-2,500 Square Feet 2,500-3,000 Square Feet
Loosely Sealed 80-90 pints 95-110 pints 120-150 pints
Moderately Sealed 70-80 pints 85-95 pints 110-120 pints
Tightly Sealed 60 pints 70 pints 90 pints

To conclude, the better the basement is sealed, the lower capacity of the dehumidifier required. 

What Size Dehumidifier Do I Need FAQs

  • How Big Of A Room Will A 30-pint Dehumidifier Cover?

Ans: A 30-pint dehumidifier can cover a room that measures 300-500 square feet. 

  • Do Dehumidifiers Use A Lot Of Electricity?

Ans: There is no direct answer to “do dehumidifiers use a lot of electricity.” This is because many factors influence a dehumidifier’s running costs—for example, wattage, size, internal mechanism, level of humidity, etc. 

The more the wattage, room size, internal components, and humidity level, the more your energy bills and vice-versa. 

  • What Size Dehumidifier Do I Need For 1,000 Square Feet?

Ans: A 1,000 square feet area requires a 50-pint capacity dehumidifier to maintain the optimal relative humidity levels. 

  • What Size Dehumidifier Do I Need For 1,500 Square Feet?

Ans: For a 1,500 square feet area, a dehumidifier with at least 60-pint capacity is the best choice. 


So, here you go. Any humidity level between 30% and 50% is considered optimum. If humidity is too low, say 10% or 20%, it can lead to dry lips, dry skin, and more. On the other hand, if it’s too much, say, 60% or 70%, your house will soon become a breeding ground for mold, dust mites, or bacteria. 

If the place where you live is notorious for its high humidity levels, having a dehumidifier is a must. But note that there’s nothing like “one size fits for all” here. 

What size dehumidifier you need depends on many factors, as discussed above. Please read them before deciding and avoid spending unnecessarily on energy and maintenance bills. 

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