5 - Heat Pump Dryers

Electrify Brookline | How-To Guide #5

For most of us, having a washer and a dryer is a necessity – we’re used to throwing our dirty laundry into the washing machine and then into the dryer, closing the door, and starting it up.

But your dryer is a significant contributor to emissions. Current technology is part of the problem. Most dryers in the United States draw in air, heat it and use it to evaporate water from the clothes, then vent it outside. Dr. Kyle R. Gluesenkamp, a researcher at the Oak Ridge National Laboratory, compared that with boiling off water on the stove. It takes a lot of time and a lot of energy.

The most energy-efficient drying method – air drying on a rack or clothesline either inside or outside – requires zero electricity or gas and could save millions of tons of greenhouse gas emissions each year. But this option is not always possible – maybe you need things to dry more quickly, or you just don’t have the space.

This How-To Guide, while it strongly recommends air drying as a top option, will focus on the next best option – a heat pump dryer.

What Is a Heat Pump Dryer?

A heat pump dryer is a “closed loop” system - similar to a heat pump water heater, or an air conditioner or refrigerator running in reverse – that uses a condenser to heat the air, remove moisture from the clothes and then reuses the air once the moisture is removed. It does not release warm, humid air through a dryer vent to the exterior of the home as a conventional dryer does, so it doesn’t require a vent. But it does need to drain. Either a hose is run from the dryer to a drain, or a removable tank collects water for up to two cycles before it needs to be emptied.

Because these dryers don’t require vents, they tend to be common in Europe, where you can’t always punch a hole in the wall of your pre-20th century building, and they help to significantly lower household energy use in Europe as compared with the US. There’s an excellent video that explains how heat pump technology works.

How Can This Help the Climate?

In most households, the largest source of energy use and climate emissions is from the heating system and water heating. But appliances can also be a significant source of emissions, and the clothes dryer is the third-most energy-hungry appliance, after the refrigerator and washing machine. According to ENERGY STAR, which tests and certifies energy-efficient appliances, heat pump dryers use significantly less energy than other dryers, whether electric or gas.

Questions About Electricity

Most heat pump dryers will require a 240 volt electrical circuit, although a few will work on 120 volts. Because you may need to make some electrical changes, being proactive can be a good strategy – contact your electrician or installer before you are ready to make the switch. You’ll need to provide the specifications of the particular appliance model you intend to install, and have your licensed electrician verify your panel capacity and install the appropriate circuit. You can learn more in our How-To Guide #7 - What About Electricity.

What Choices Are There?

Heat pump dryers come in two sizes: standard (about 27” wide) and compact (about 24” wide). You can choose a dryer that is heat pump only, or a hybrid dryer that will use electric heat should you need your laundry to dry more quickly. Another option is installing a typical electric clothes dryer – these do not run as efficiently as heat pump clothes dryers, but they have the same benefit of running without gas.

The ENERGY STAR website has a product guide that will help you find products that they have rated.

Other Considerations

  • Heat pump dryers typically take longer to dry clothes than vented dryers. According to ENERGY STAR, though, some newer models have short dry cycles (under 50 minutes).
  • Heat pump dryers are more expensive than vented dryers, but more rebates are becoming available.
  • For a heat pump dryer to function correctly, it needs to be in a ventilated space. For this reason, the dryer will not be able to function correctly if it is in a spot like a utility closet as it will end up reabsorbing the warm air it just expelled.
  • Some heat pump dryers are stackable and/or can be paired with a washer. Whatever kind of machine you use for drying, the best thing you can do to reduce energy consumption is take full advantage of the high-speed spin cycle on your washing machine. That means less water needs to be evaporated off.
  • The Energy Department also recommends only doing full loads.
  • Heat pump dryers are gentler on your clothes. The lint you find in your dryer is evidence of your clothes literally wearing away. Because heat pump dryers use less heat, they cause less damage to your clothes and generate less lint.
  • According to a report by FEMA, clothes dryer vents can become clogged with lint, causing more than 15,000 house fires every year[need a source]. The ENERGY STAR website has lots of good information on heat pump dryers as well as tips to get the most out of them.

Costs

A heat pump dryer and its installation may cost you more than a similar size gas or electric dryer and may also require electrical work; however, the price differential may be offset with available rebates and tax credits. A recent search of Home Depot in June 2023 showed a Samsung heat pump dryer on sale for just under $1,000.

Available Rebates and Tax Credits

The new federal Inflation Reduction Act (IRA) contains many rebates, including for heat pump dryers; Mass Save also offers a rebate. As these are constantly evolving, be sure to verify the latest information.

Another good resource is the Massachusetts Clean Energy Center, which includes a table on available incentives from both our state and the federal government.

How Your Neighbors Made the Switch

After moving to Brookline’s Pill Hill neighborhood several years ago, this homeowner’s family decided to undertake a major project that was spurred on by their desire to reconfigure and upgrade their basement. They had never considered electrifying their home, or knew that was desirable or even possible, until the homeowner joined Mothers Out Front (MOF) Brookline and began attending their meetings. There she learned both about the health impacts and the climate impacts of the gas heating and gas appliances in their home and wanted to work toward eliminating all the gas piping in the house.

So when it was time to upgrade the basement, she began doing a lot of research and the family decided to completely electrify the systems and appliances housed there, including the whole house heating, the water heater and the clothes dryer. Even though their existing gas dryer was working fine, they felt it didn’t make sense to keep any gas appliances.

When deciding on the right clothes dryer, they selected a heat pump dryer rather than a conventional electric dryer for two reasons: first, the heat pump dryer would use less electricity and second, it wouldn’t require a vent, so there would be more flexibility as to where it could be located.

They chose a full-size heat pump dryer, mainly because they wanted to be able to do a full-size dryer load that would match the size of the loads that could be handled by their washing machine. The only full-size heat pump dryer currently available is made by Whirlpool and that’s what they purchased. Other heat pump dryers have a smaller capacity – about 4 cubic feet for a compact dryer compared to about 7 cubic feet for a full-size dryer.

The basement renovation is not complete, but the new dryer has been installed and is working well. The homeowner has observed a couple of things:

  • The new dryer doesn’t make a lot of lint and there seems to be less damage to the clothing. The clothes actually feel like they’re better quality and less worn down than they’d been with the old gas dryer. Even delicate items come out well.
  • There are two lint screens that need to be cleaned – the regular screen in the front door of the dryer and a second one of finer material that leads to the heat exchange equipment.
  • The dryer isn’t noisy, and it doesn’t make the surrounding space hotter or colder so it could be located in any room in the house and wouldn’t affect the temperature.
  • The home already had 200 amp electrical service, but they did need to add a circuit breaker for a 240 volt line for the dryer.
  • The heat pump dryer takes a longer time to dry clothes – around 1 hour 45 minutes.

This home now has no gas piping! The work that has been and is being done, occurred during 2023 and the homeowner will be eligible for Mass Save rebates and Federal tax credits.

About Electrify Brookline

Electrify Brookline is a collaboration between the Town of Brookline’s Zero Emissions Advisory Board (ZEAB), Mothers Out Front Brookline and Climate Action Brookline. Our goal is to provide clear information to guide the community on the path toward electrification – improving the energy efficiency, health and comfort of their living spaces while reducing climate-damaging emissions to preserve a livable future for all.

IMPORTANT: Verify with your installers that they have the proper licenses and insurance, and confirm that they have or will obtain all required permits and inspections from the Town of Brookline.

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