The essentials in 30 seconds
A heat pump tumble dryer uses a closed loop of air, so it needs no vent. Warm air passes through the drum and absorbs moisture from the clothes. It then goes through an evaporator, which cools it so the water condenses and is collected in a tank (or drained through a hose). The now drier air is reheated and sent back to the drum. The heat comes from a heat pump: a compressor squeezes a refrigerant gas until it is hot, and that heat passes to the air in a heat exchanger, as Miele's instructions describe. Because the air only reaches about 50 °C, against 70–75 °C in a condenser dryer, cycles are longer, but energy use is much lower: Samsung and Beko say up to 50 % less.
- Clean the fluff filters after every cycle and the heat exchanger regularly; fluff there slows drying.
- Most new tumble dryers sold in Great Britain will be heat pump models once new efficiency rules apply.
How a heat pump tumble dryer works
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01
Warm air into the drum
Warm, dry air is blown into the drum and absorbs moisture from the tumbling clothes.
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02
Through the filters
The moist air passes the fluff filters, which catch lint before it reaches the heat pump.
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03
Evaporator
The air flows over the evaporator, a cold heat exchanger. As it cools, the water condenses out (Bosch, Beko).
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04
Water to the tank
The condensed water runs into the condensed water container, or out through a drain hose if the dryer is plumbed in.
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05
Compressor
Meanwhile the compressor compresses the refrigerant gas, which raises it to a high temperature (Miele).
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06
Heat exchanger
The hot refrigerant gives its heat to the drying air as the air passes the second heat exchanger (Miele).
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07
Back to the drum
The reheated, dry air returns to the drum and the loop repeats until sensors detect the clothes are dry.
The same refrigerant goes round its own sealed circuit, picking up heat at the evaporator and releasing it at the heat exchanger. That is why a heat pump dryer makes a humming noise: Miele says it is normal.
Heat pump, condenser and vented dryers
| Heat pump | Condenser | Vented | |
|---|---|---|---|
| Heat source | Heat pump reheats the same air | Heating element heats air for each cycle | Heating element |
| Air | Closed loop, reused | Heated repeatedly; moisture condensed inside | Hot, moist air blown outside through a vent |
| Maximum temperature | About 50 °C | Usually 70–75 °C | — |
| Water | Tank or drain hose | Tank or drain hose | Vented outside |
| Drying time | Longer | Faster | — |
| Energy | Up to 50 % less than condenser or vented (Beko, Samsung) | Higher | Higher |
| Purchase price | Higher | Lower | — |
Beko's figures for an 8 kg dryer: a standard condenser model uses about 561 kWh a year and 4.75 kWh per full cotton cycle; an A+ heat pump about 265 kWh and 2.18 kWh. Its example cotton eco cycle takes 142 minutes in a condenser dryer and about 197–209 minutes in a heat pump model.
Why heat pump dryers take longer
The air is cooler, so evaporating the same water takes more time. Which? says heat pumps can take almost twice as long as condensers in its tests, and Beko puts the longer time down to the maximum of about 50 °C. The upside is that lower heat is gentler on fabrics, Beko and Samsung say. To keep cycles short, Miele advises spinning at the highest speed in the washing machine (about 20 % energy saved spinning at 1,600 rpm instead of 1,000), drying full loads, keeping the room not too warm and well ventilated, and cleaning the fluff filters after every cycle. Miele's room range is 2–35 °C: avoid rooms where it can freeze.
Looking after a heat pump dryer
- Fluff filter: clean it after every cycle, says Electrolux; wash it under running water if it is very dirty or limescaled, so you can see through it against the light.
- Heat exchanger (condenser): Electrolux says to check it at least once a month and clean it when the symbol flashes, with a damp cloth or a vacuum brush. Wear gloves: the metal fins can cut. Never run the dryer with it blocked by fluff.
- Self-cleaning: some models clean it automatically; LG's Condenser Care uses water condensed during drying.
- Water tank: empty it after each load unless the dryer drains through a hose.
- Access differs by model: follow your user manual.
Rules for new dryers in Great Britain
The UK government has decided that only tumble dryers with an Energy Efficiency Index below 85 will stay on the market, with an eco programme as default or directly selectable, at least 80 % condensation efficiency and strict standby limits. It says this phases out inefficient gas-fired, vented and condenser models and shifts the market to heat pumps. The rules start 10 months after the regulations are laid; Which? expects most dryers on sale from 19 January 2027 to be heat pump models, while existing stock can still be sold. Washer-dryers are not covered. Our best washing machine guide explains the A to G label.
Heat pump tumble dryers: FAQs
How does a heat pump tumble dryer work in simple terms?
It keeps the same air going round: the air takes water from the clothes, a cold evaporator condenses the water out, and a heat pump reheats the air for the next pass.
Why does a heat pump dryer take longer?
It dries at about 50 °C instead of the 70–75 °C of a condenser dryer, so evaporating the water takes more time.
Does a heat pump dryer need a vent?
No. The air stays in a closed loop and the water goes to a tank or a drain hose.
Is a heat pump dryer cheaper to run?
Yes: Beko and Samsung say up to 50 % less energy than conventional dryers; Beko's 8 kg example uses 2.18 kWh per cotton cycle against 4.75 kWh.
Why is my heat pump dryer humming?
The compressor and heat pump make a humming noise during drying; Miele says it is normal.
Sources
Manufacturer explanations, operating instructions and UK government response, checked on 3 November 2026 (03/11/2026).
- Bosch UK · Heat pump dryers: the future of sustainable laundry ↗Closed heat exchange, lower temperature; air through the drum, then an evaporator removes moisture, air reheated; reheats circulating air instead of a heating element. Read.
- Beko UK · Heat pump tumble dryers: efficiency, pros and cons ↗Closed loop, water to a tank; clean filters and evaporator; 8 kg cotton eco cycle 142 min condenser, about 209 min A+ and 197 min A++; 561 kWh/4.75 kWh vs 265 kWh/2.18 kWh; up to 50 % less; gentler on fabrics. Read.
- Beko UK · What is heat pump technology? ↗Absorbs moisture, cooled in the evaporator, reheated; closed loop. Read.
- Samsung UK · Heat pump vs condenser ↗Recycles hot air; up to 50 % less energy; slightly longer cycles; higher price; condenser heats fresh air each cycle. Read.
- Miele · Operating instructions, heat pump tumble dryer (PDF, en-AU/NZ) ↗Refrigerant compressed by the compressor, heat transferred to drying air in the heat exchanger; humming normal; R290 flammable and explosive if it leaks, what to do; wait 1 hour after installation; room 2–35 °C; energy tips (spin speed, full loads, filters). PDF read.
- Electrolux UK · Cleaning tumble dryer filters and condenser ↗Filter after each cycle; check condenser at least monthly; gloves; damp cloth or vacuum brush; don't run when blocked. Read.
- LG Canada · Heat pump (condenser) dryer not heating ↗Condenser Care cleans lint using condensed water. Read.
- GOV.UK · Raising standards for household tumble dryers: government response ↗EEI below 85; eco programme; 80 % condensation efficiency; standby limits; phases out gas-fired, vented and condenser models; 10-month transition after the SI is laid. Read.
- Which? · The tumble dryer "ban": what does it mean for you? (9 July 2026) ↗Condensers usually up to 70–75 °C, heat pumps around 50 °C; almost twice as long in tests; most dryers from 19 January 2027 heat pumps; washer-dryers not affected. Read.
Dryer taking longer than usual?
Clean the fluff filters, check the heat exchanger for fluff and spin your washing at the highest speed before drying.