If you’re in the market for a new tumble dryer, you might have come across the term ‘heat pump’, but what is a heat pump dryer and how do they work?
Heat pump dryers make up the larger part of our best tumble dryers list, so make sure to head over there if you’re looking for buying advice on specific models. Likewise, our best washing machines list is the go-to place for all washer recommendations, so don’t forget to check that out if you’re looking to upgrade both home appliances at once.
Lastly, if you’d like to learn more about the difference between heat pump dryers and other types of tumble dryers, make sure to visit our versus guide to condenser vs vented vs heat pump dryers.
What is a heat pump clothes dryer?
This type of tumble dryer that uses a heat pump to generate heat to dry clothes, rather than a traditional electric heater that a condenser dryer would use.
Heat pumps are common in many appliances, and move heat from one place to another using a refrigerant, so are incredibly energy efficient. This technology is used in fridges and air conditioning, moving warm air out to provide cooling; and in air-source heat pumps, which use air from outside to create heat for your water and radiators.
In a tumble dryer, a heat pump is used in a closed-loop system, recycling the warmth in the air continuously rather than constantly providing heat, as with a vented or condensing tumble dryer. This dramatically reduces running costs, and is reflected in the higher energy ratings associated with heat pump dryers, though these will vary from model to model.
While heat pump dryers are cheaper and more energy-efficient to run, its worth noting that they are often more expensive to buy upfront.
How does a heat pump dryer work?
Heat pump dryers work by sending air to the drum, which is heated using a condenser. The hot air absorbs moisture from your cloths, before passing through an evaporator, which cools the air to extract the water and send it to a tank. The air is then recycled and reused, passing through the warm condenser again.
The combination of recycling the air and not requiring a heating element, heat pump tumble dryers are much more efficient than other types. Both vented and condenser tumble dryers use a heating element and expel hot air, so they constantly have to generate new warm air.
As an example, in our tests the Haier HD90-A3Q397U1 heat pump tumble dryer used 0.813kWh of power on the hanging dry setting, which meant that the cycle cost around £0.20 (assuming a cost per kWh of 24.5p). The Indesit BDE 107436 WV UK washer dryer, which is a condenser dryer, used 2.387kWh on the same cycle, which is around £0.70 – that’s 3.5x more expensive.
All of the heat pump tumble dryers we’ve reviewed (and the vast majority of other types) use a humidity sensor that lets the machine stop automatically when it detects your clothes are at the right level of dryness.
Does a heat pump dryer shrink clothes?
Heat pump dryers might actually be less likely to shrink your clothes than other types of dryers. This is because they run at lower temperatures and, as a result, generate less friction compared to other types of dryers.
Lower heat also helps prevent damage to clothing fibres and colours from fading.
Do heat pump dryers need to be vented?
Vented dryers take their name from the vents that are required to extract and expel hot, moist air from the machines to the outside. Condenser tumble dryers remove the moisture from the air, but do expel hot air into the room. With a heat pump tumble dryer, air is kept inside the machine and water is sent to a tank that has to be emptied at the end of a cycle. This means you can place them wherever you want.
However, heat pump and condenser dryers both have the option of using a drainage pipe instead of the tank, sending extracted water into the drain instead.
