The time has come for ventless heat pump clothes dryers to join heat pump water heaters and heat pump HVAC systems in new homes, renovations, and appliance replacements. Why is this important? Number one is that global warming is a crisis quickly turning into a tragedy, and any step we can take to reduce energy use and carbon emissions is of paramount importance. This includes retiring our inefficient clothes dryers — especially our natural gas powered dryers that more directly contribute to global warming.

Number two, all homes should get on the path to becoming all electric because electricity is a better way to perform household functions, including clothes drying — as electricity can be generated from solar, wind, and other clean energy sources. Heat pumps, including heat pump clothes dryers, are the most efficient ways to use electricity and should be an integral part of most all-electric homes. Their low energy use can easily be offset by solar panels or by purchasing renewable energy. They have some distinct advantages, as well as some disadvantages, compared to traditional dryers.

How They Work in a Nutshell

Conventional electric dryers use resistance heating elements to heat the air and then dump moisture and heat out through a duct to the outside, along with a considerable amount of conditioned air from the home. Heat pump clothes dryers are a more efficient technology that works similarly to a refrigerator in reverse. They use a compressor and a refrigerant-filled coil to heat the air inside the dryer. This hot air removes moisture from fabric in the drum. After capturing moisture, the air flows to a cold evaporator coil where the water vapor condenses into a collection pan. The dry air then passes through a condenser where it is reheated and circulates back into the drum instead of exhausting through a duct to the outside. Many models offer two methods for removing the collected moisture. First, water can be pumped through a drain hose into the washer drain, a nearby sink, or a floor drain. Second a built-in collection tray can easily be pulled out and emptied after each load.

These dryers use up to 50% less energy because the heat pump requires less electricity to run the compressor than a conventional resistance heating element and space- conditioned energy is not wasted. As a result they receive the highest ENERGY STAR ratings. To learn more, here is one company’s video on how heat pump dryers work and another video from Ask This Old House. While heat pump dryers are technically condenser dryers, and both condenser dryers and heat pump dryers are ventless, condenser dryers without heat pumps are much less energy efficient.

Advantages

In addition to energy savings, these dryers are gentler and less abrasive on clothes. Hot air is rough on clothes and causes excess wear and shrinkage. Since the air temperature used for drying is much lower and moisture sensors limit overheating. Clothes are dried more consistently and carefully, saving money on replacing clothes. Also, heat pump dryers can be more convenient. Because they are so energy efficient, people may feel freer to use them any time without concern for excessive electric bills. Because of lower temperatures, it is safer to turn them on and leave the house or go to bed.

These dryers are easier to install in small apartments or interior rooms because they do not need access to an outside vent to expel the moisture-laden hot air, as do conventional dryers. And you do not even need a dedicated laundry room. This makes the design of new homes and apartments more flexible and makes adding a dryer to a small apartment easier. Without a duct, you no longer have to remember to clean out the exhaust duct and external vent every six months, as you do with traditional dryers in order to prevent inefficient drying and dryer fires.

Currently, there are many 4-cubic-foot heat pump dryer models available that appear to be comparable in price to similar-sized conventional models. These dryers have a long track record of successful use in Europe, where the smaller sized ventless dryers are the standard. In many U.S. homes and apartments, this compact size may be an advantage. In some states rebates are available on these energy-efficient models. ENERGY STAR, in addition to providing energy ratings, provides information on the rebates available in each state.

Disadvantages

In addition to removing lint from the usual lint filter, there is another area that needs to be cleaned at the bottom of most heat pump dryers. In many models, the heat pump coils also need to be cleaned with a brush and/or a vacuum every 30 days or so, which should take less than five minutes. Because they use lower temperatures, heat pump condensing dryers also take longer to dry the clothes, perhaps up to twice as long, depending on load size and model. Because the technology is relatively new and the options for dryers are many, be sure to check user reviews and prices before selecting one. One drawback for larger families is that currently only one 7-cubic-foot heat pump dryer model is available — a Whirlpool Model WHD560CHW.

Forget About Payback

The most widely available and least expensive heat pump models are 4 cubic feet in size and cost around $1000, while a standard electric 4 cubic foot vented dryer also cost about $1000. So if you are looking for a compact dryer, payback is not an issue and you will earn about $75 per year on energy savings.

Larger, 7-cubic-feet standard entry level vented dryers can be found for close to $600. If you select a 4 cubic foot heat pump dryer instead, it will cost about $400 more while saving on average $75 per year in states with average energy costs. If the added cost of a heat pump clothes dryer is rolled into a new home mortgage or a remodeling loan, they can pay for themselves from day one, as the estimated yearly energy savings ($75.00) will be greater than the added yearly payment for principal and interest ($32 at 5%) to cover the added costs of a heat pump dryer.*

Whirlpool’s 7-cubic-foot heat pump dryer costs around $1300. User reports on this model have been positive. Purchasing it would make the added cost over $700 compared to an entry model 7 cu. ft. vented dryer. If this extra cost is included in the mortgage, it will add $45 in yearly interest and principal — again significantly less than the yearly energy savings.

An Even Better Option: Air Drying

Alternatively you can air dry your clothes with any of the available well-designed clothes racks to hang the clothes. If you have a mini-split heat pump HVAC system for heating and cooling your home, place the drying rack under your indoor unit, with the vent aimed down and the heat raised. It’s a heat pump clothes dryer of a different kind. But for those who want the convenience of a modern clothes dryer and a lower carbon footprint, the time has come for heat pump dryers.

*Financial calculations are dependent on individual financial circumstances and are very sensitive to changes in prices, interest rates, and fees, so it is important to do your own due diligence.