Heat Pump Dryer

A heat pump dryer is a more efficient electric dryer which is often ventless. In a traditional dryer the warm and humid air coming out of the drying clothes is vented out and the heat content of that air is wasted. A heat pump dryer recaptures a part of that heat and turns it back into the dryer using a special device. This makes the dryer about 50% more energy efficient at the expense of additional drying time.  A heat pump dryer can cut the clothes drying energy bill by half.

Cost Range

$1,100 - $1,500

About the technology

How it works:  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. It also recycles some of the heat by not letting it vent out of the dryer. This technology allows a HPD to use about one-half as much electricity as a traditional electric dryer

Types of Systems:  There are typically 3 different sizes. Portable table top units that can do a 3 kg load (3 cu ft), a standard unit with about 6-7 kg load (4-5 cu ft) capacity and large units which are more popular in the Americas with about 9-11 kg (7-8 cu ft) capacity. 

Special Requirements:  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. Hence, 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.

Economics: The cost of a heat pump dryer is generally 30-40% higher than a conventional electric clothes dryer.  

Maintenance: As with any clothes dryer, it’s necessary to periodically clean the lint filter.  Additionally, some heat pump dryers require the removal of lint from the condenser every several months.

Environment:  The magnitude of environmental benefit depends largely on the type of dryer you’re switching from.  The biggest impact occurs when switching from a natural gas or propane dryer to a heat pump dryer (especially if you’re using electricity with a low carbon content). When switching from traditional electric dryers the benefit is lower. Of course if you can live with a clothes line that is the best from an environmental point of view.

Frequently Asked Questions (FAQ)

1. What is the difference between a conventional clothes dryer and a heat pump dryer?

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.

2. How long does it take to dry clothes with a heat pump dryer?

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

3. Do heat pump dryers need to be vented?

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.

4. What sizes are available?

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

1. How expensive are heat pump dryers?

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.

2. Do heat pump dryers save money over normal electric dryers?

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. If you use natural gas for drying your clothes, you’ll likely not save any money on your energy bills.

1. What kind of maintenance issues arise?

As with any clothes dryer, it’s 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 needs to be cleaned of lint as with a conventional dryer.) 

2. How reliable are heat pump dryers compared to conventional clothes dryers?

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.

1. Is there a greenhouse gas reduction benefit of using a heat pump dryer?

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 or propane 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. 

1. Are there any special installation steps for a heat pump dryer?

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.

2. Are stackable washer dryer models available?

Yes, stackable heat pump dryers and washer models are available.  This can be an effective way to save space.

3. What are the effects on clothing when a heat pump dryer is used?

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.

4. Are heat pump dryers safe?

Yes, they are probably safer than conventional dryers.  Lint trapped in a conventional 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.