Taming the other energy hog lurking in your basement

Posted on May 14, 2015 by
Joanna Mauer

Last summer, the U.S. Department of Energy (DOE) issued new efficiency standards for furnace fans, which are a little-known energy hog that may be lurking in your basement. Today, DOE proposed new standards that would help tame another energy hog that may be in your basement—dehumidifiers. However, while the proposed standards would be a good step towards cutting dehumidifier energy waste, they leave large cost-effective energy savings on the table.

For the 13% of homes with dehumidifiers, their consumption of 600-900 kilowatt-hours (kWh) per year amounts to 6-8% of an average household’s electricity consumption. By comparison, a typical new refrigerator consumes about 450 kWh on average.

DOE estimates that dehumidifiers meeting the new standards sold over 30 years would reduce US electricity consumption by 36 billion kWh, an amount equal to the annual energy consumption of 3.3 million U.S. households, and net savings of $1.0-2.3 billion for consumers. However, higher standards that DOE evaluated, but did not propose, would more than double the national electricity savings to 90 billion kWh, and increase consumer savings to $2.1-5.0 billion.

The new standards would cover both portable dehumidifiers and whole-home dehumidifiers. Portable dehumidifiers make up more than 95% of sales and can be easily moved from one room to another. Some portable dehumidifiers collect water in a bucket, while others can be connected to a drain. Whole-home dehumidifiers are often used in conjunction with a home’s HVAC system and are designed to be connected to ductwork that supplies conditioned air to a whole house.

Dehumidifiers work by using a refrigeration system to cool air to the point where moisture in the air condenses. The proposed standards could be met by using more-efficient compressors and larger heat exchangers.

The current standards for dehumidifiers are based on efficiency performance at an ambient temperature of 80o F. However, most dehumidifiers are used in basements, where temperatures are typically significantly lower than 80o F. The new proposed standards would instead be based on efficiency performance at 65o F, which better reflects how dehumidifiers are actually used in homes.

DOE is scheduled to publish a final rule by January 2016, and the new standards would take effect three years later.