Dehumidifiers work to remove extra moisture from your room or home by regulating humidity levels. This reduces mold, mildew, water damage and water-born bugs. To find out what size dehumidifier you need, you will need to figure out your room size and humidity level, both of which are easy to find out.
Dehumidifiers are Measured in Pints
Dehumidifiers are sized by pints, that is, pints of water/moisture removed in one day. In the case of a 40-pint dehumidifier, it means that this unit removes 40 pints of moisture per day, which is equivalent to 5 gallons. The size of the area you want to dehumidify is an important factor to consider. Larger areas will usually need a dehumidifier with a pint capacity.
Room Size
To measure your room size, take a tape measure and measure the length of the room by the width and multiply the two numbers. If you have a room 12 feet long and 10 feet wide, your area is 120 square feet.
Humidity Level
Moderately Damp: The air feels too humid to be comfortable. There might be an odor from the excessive humidity.
Very Damp: The room feels damp and smells. There may be damp spots on the walls or floors.
Wet: Water beads on the walls and floors. There might be seepage on the walls near the edges of the room.
Extremely Wet: Water pools on the ground in puddles. The room will feel too humid and uncomfortable. There may be mold.
Calculating Your Dehumidifier Size
Once you know your room size and humidity, you can find out what size dehumidifier you need by using this chart:
Other Factors in Choosing Dehumidifier Size
If you live in a very humid region you will need to increase the number of pints on your dehumidifier, by at least 10 pints. If there are many windows or more than 1 door, add 5 pints. If there is a washer or dryer unit near the room add 5 pints as well.
In general, if there is any doubt you should increase pint size rather than decrease. This is because you can set your dehumidifier to a low setting. This is better than having a dehumidifier that doesn’t do its job—which leads to mildew and mold.