Heat Pump Dryer FAQ

Basics

A conventional dryer creates the heat for drying by burning natural gas or using electric resistance heating elements. A heat pump dryer (HPD) is more energy efficient because it doesn’t create heat, but instead uses an electric-powered compressor, heat exchangers, and a refrigerant to move heat from the surrounding air into the dryer’s drum. This technology allows a HPD to use about one-half as much electricity as a traditional electric dryer. When replacing a natural gas dryer, a HPD can help reduce your home’s carbon footprint.

Heat pump dryers operate at a lower temperature than a conventional dryer. Accordingly, drying times can be significantly longer.

In most cases, no. Conventional dryers expel warm, moist air through a vent to outside the building. Heat pump dryers, however, don’t require venting because they condense the moisture into water that is sent to a drain or a collection tank. Some manufacturers market a hybrid dryer where the heat pump is optional and the consumer can choose to bypass it with conventional electric heating if faster drying is needed. Such dryers must be vented.

Various capacity heat pump dryers are available, but the most popular ones come in two sizes – a smaller 3 – 4 cu ft capacity and a larger 7 – 8 cu ft capacity.

Economics

The cost of a heat pump dryer is generally in the range of $1,100 to $1,400.  This is significantly more than low-cost traditional clothes dryers, which can often be found for $500 to $900.

Since they use about half the energy to dry, a heat pump dryer’s ongoing energy costs are lower than that of a conventional electric dryer.  Depending on how often you use the dryer and the electricity costs in your area, you could possibly recoup your initial additional investment in as little as 5 years. 

Maintenance

As with any clothes dryer, it is necessary to periodically clean the lint filter.  Additionally, some heat pump dryers require the removal of lint from the condenser every several months. Finally, heat pump dryers produce water that must be either removed through a drain or collected in a tank. If you use the tank option, it must be emptied periodically. (Note that in most cases heat pump dryers do not have a vent or ducting that need to be cleaned of lint as with a conventional dryer.) 

This is a relatively new technology in the US, so long-term reliability data are still being collected here. While manufacturers’ warranties are similar to those of traditional dryers, the design of a heat pump dryer is more complicated than a conventional dryer and that may have an adverse effect on long-term reliability.

Environment

Yes, but the magnitude depends largely on the type of dryer you’re switching from.  The biggest impact occurs when switching from a natural gas dryer to a heat pump dryer (especially if you’re using electricity with a low carbon content).  If switching from a conventional electric dryer, the greenhouse gas benefit will likely be less dramatic, but will still be in the neighborhood of a 50% reduction. 

Steps to use

In many cases a condensate drain pipe is added to remove the water produced by the heat pump.  If this presents a problem, heat pump dryers come equipped with a collection tank, but that tank must be emptied periodically. Except for hybrid models, heat pump dryers are ventless, so no outside venting duct is needed.

Yes, stackable heat pump dryers and washer models are available.

Heat pump dryers operate at a lower temperature than a conventional dryer, and as a result can take a significantly longer time to dry a load.  The lower temperatures are beneficial to clothing but the longer tumbling time adds more wear and tear.

Yes, they are probably safer than conventional dryers.  Lint trapped in a clothes dryer can sometimes catch fire and spread to the house via lint trapped in the vent ducting.  Since a non-hybrid heat pump dryer doesn’t require venting, the fire danger is reduced.