What Size Dehumidifier Do I Need?

Presidential Heating & Air Conditioning

Gaithersburg HVAC Contractors


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Dehumidifier in living roomShopping for a portable dehumidifier can be a challenge because many people are unsure what size dehumidifier they need. If you are dissatisfied with your current dehumidifier, it is likely that it is not the proper size for your needs. It might be that the room you have it in is too large, or that the space is too humid and it lacks the capacity to remove an adequate amount of moisture.

Many people do not realize that dehumidifiers come in different sizes and that these sizes are precisely calculated. Each dehumidifier you see is designed with specific humidity and space requirements in mind.

Determining what size your dehumidifier needs to be is very simple, but only if you have the correct information. Even then, it can be challenging because the sizing of dehumidifiers is not always easy to understand, and requires some work on your part. We will help you understand what the different sizes of dehumidifiers mean and how to determine what size is right for you.

How Are Dehumidifiers Sized?

Dehumidifiers are sized based on the amount of air they can remove moisture from. A given dehumidifier’s removal capacity is measured based on the volume of air it can dehumidify over the course of a 24-hour period. This is expressed in the pints of moisture that it removes during that time.

So, a 30-pint dehumidifier can remove 30 pints of moisture from the air in 24 hours. The confusing part of this is that they are not sized based on the size of the space they can dehumidify, so you will need to be able to calculate that on your own.

The reason that dehumidifiers are not rated by square footage is that volume is not the only thing that needs to be measured. The moisture level in the air matters just as much. A dehumidifier that works just fine in a large room with 50% humidity might struggle in the same room if the humidity goes up to 70%.

Choosing Your Dehumidifier’s Capacity

In general, for slightly to moderately damp spaces, a 10-pint dehumidifier can handle 500 square feet, and a 26-pint dehumidifier can handle 2,500 square feet. For 1,000 square feet, you need a 14-pint dehumidifier, for 1,500 square feet you need 18 pints, and so on. Essentially,you need to add four pints for each additional 500 square feet.

Dehumidifier soaking up humidity in damp roomIf the space is very damp- meaning there are constantly musty smells and damp spots on the floor or walls- then you need a higher capacity dehumidifier for smaller volumes. In these cases, you start off with 12 pints for a 500 square foot space and add five pints for every additional 500 square feet.

If the space is actually wet and you see seepage or sweating on the walls and floor, you will again need more capacity. You need 14 pints for the first 500 square feet, and add six pints for each additional 500 square feet.

Finally, for spaces wet enough to have standing water, you will need high-capacity dehumidifiers. For 500 square feet, you will need a 16-pint dehumidifier. For each additional 500 hundred square feet, you will need another seven pints of capacity from your dehumidifier. It is a good idea to purchase a dehumidifier that is rated for a larger space than what you actually need, as this will save energy.

Considering Room Conditions

Once you know the square footage of the space and have an idea of the capacity you need in a dehumidifier, the final step is considering a few more things about the room. If your home is in a humid climate, add 10 pints to the needed capacity. Your space may not feel as damp as it really is because of the humid climate.

If multiple people will be using or living in the space, add five pints. People increase the humidity in the room in a couple of ways. First, we sweat. When we sweat our bodies are using evaporative cooling to lower our body temperatures, but the moisture is now in the air. We also add moisture to the air just by breathing- our breath is naturally humid, and that moisture stays in the air when we breathe out.

If the room has multiple doors and windows, add five pints. Doors and windows can have leaks in them which increases humidity, but they also let in humidity when they are open. Even just opening the door to walk through it and closing it right after will let a lot of humid air in.

If the washer and dryer are nearby, add another five pints. Washers add humidity to the air in small amounts, but the dryer is the real culprit. To dry your clothes the dryer has to remove the moisture and send it somewhere. Most of it will go outside, but not all of it. Clothes fresh from the washer are completely saturated with water, and the air around a dryer will get very humid, very fast.


Woman turning on her dehumidifierIf you are considering purchasing a dehumidifier for your home, it may be helpful to speak with a professional. With so many different factors to consider, it is very easy to make a mistake and buy a dehumidifier that will not be able to effectively dehumidify your space. At Presidential Heating and Air, our expert staff would be more than happy to help you.

Since they are professionals, you can be sure that they will not be as prone to making mistakes in calculating the size you need. One of the biggest challenges people have is not being certain about the moisture level in their room, and that is a crucial part of determining the size of the dehumidifier you need.

Contact us today to get help with choosing a dehumidifier. We will make sure that you get one that is the ideal size for your home and the humidity conditions in it.

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