Time to Dust off the Dehumidifier

June 04, 2015

Whether you own or rent your home, there are many “must haves.” Dependable heating and cooling systems, bright lights, and durable appliances are a few that come to mind.

If you’re accustomed to our hot and humid Massachusetts summers, you’ll know that a well-functioning dehumidifier is one of these must-haves. Dehumidifiers are often a mainstay in humid, non-conditioned areas within homes, such as cellars and crawl spaces. They reduce humidity and mold, preventing long-term health problems.

Although dehumidifiers are greatly needed in our part of the country, especially along the coastline, they are one of the highest energy consuming appliances in your home – second only to your clothes dryer! Why? Dehumidifiers must operate constantly to effectively address potential mold and mildew problems. They are best suited for temperatures above 65 degrees and relative indoor air humidity above 50 percent. This means dehumidifiers’ run cycles can encompass half of the year! In comparison, air conditioners are only used for a quarter of the year in the Commonwealth.

Speaking of air conditioners.

Air conditioners and dehumidifiers are actually closely related, but they serve different purposes. Like an air conditioner, a dehumidifier also uses refrigeration coils, compressors, and fans to function. Although their seasons overlap and they both operate using the refrigeration cycle, dehumidifiers and air conditioners should not be used in the same way. So when is it appropriate to use each of these machines?

  • An air conditioner is ideal when cooling is the primary aim, even if the air conditioner also dehumidifies a space.
  • A dehumidifier is best suited where moisture is an issue or causes discomfort, but where cooling is not needed – like a basement. This is because the air conditioner rejects heat generated in the refrigeration cycle to the outside of the house, while a dehumidifier does not.

Look for efficiency.

With any appliance that is used continuously, it’s important to make sure you purchase the most efficient model available.  The best way to determine if a dehumidifier is energy efficient is to ensure it is ENERGY STAR® certified. Dehumidifiers that are ENERGY STAR certified use 15 percent less energy than standard units and can save you up to $50 annually in energy costs. That’s enough for a 70-pint unit to pay for itself in energy savings in five years or less!

For even greater savings, consider checking the unit’s energy factor to ensure you are purchasing the most efficient unit possible. A higher energy factor means a more efficient dehumidifier. Look for the energy factor on the unit’s packaging to help you choose between one model and another.

And also size.

One of the most important considerations in choosing the right dehumidifier, outside of efficiency, is its size. Dehumidifier size is measured in capacity, which is determined by how many pints of water the unit can hold after the water is extracted from the air. The guide below, developed by the Association of Home Appliance Manufacturers, offers guidance on the pint capacity needed to perform optimally for the size and climate of a given room.

Condition without Dehumidification

(in Square Feet)






Moderately Damp – Space feels damp and has a musty odor only in humid weather.

10 pt.

14 pt.

18 pt.

22 pt.

26 pt.

Very Damp – Space always feels damp and has a musty odor. Damp spots show on walls and floors.

12 pt.

17 pt.

22 pt.

27 pt.

32 pt.

Wet – Space feels and smells wet. Walls or floors sweat, or seepage is present.

14 pt.

20 pt.

26 pt.

32 pt.

38 pt.

Extremely Wet –Drying laundry, wet floor, high load conditions.

16 pt.

23 pt.

30 pt.

37 pt.

44 pt.


If a dehumidifier is one of your home’s must-haves, you’re in luck. The Sponsors of Mass Save® offer a $30 mail-in rebate on ENERGY STAR certified units. We also work with local and national retailers to ensure you can find the right model to fit your needs. Remember to pick the right-sized dehumidifier and use it only when needed to limit energy waste.   

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