Tumble dryer not drying — causes and step-by-step fix
Before you write the dryer off and call a technician: most 'it runs but won't dry' cases are trapped air, not a heating fault. A clogged lint filter or a blocked vent chokes the hot air, so the load stays damp and the cycle drags on for nothing. Work through these steps in order — and while you're at it you'll cut a genuine fire risk, because built-up lint is flammable.
The problem
The drum turns and the cycle finishes, but the load comes out damp — or it needs two or three cycles to dry. Sometimes the inside feels very hot and the door is scorching, or the opposite: it tumbles with no heat at all and the washing comes out as cold and wet as it went in.
Likely causes
A clogged lint filter (the number one cause, by a mile)
Every load leaves a layer of lint on the filter — and once it's saturated, it blocks the hot air from passing through and carrying the moisture out. The result: the washing stays damp and the cycle drags on. The filter needs clearing before every load, not once a week. This is also the single most important step against fire.
A blocked vent hose or stuck outside exhaust flap (vented type)
A vented dryer pushes the damp air outside through a hose, and that hose has to be clear and open. If it's packed with lint, crushed or coiled behind the machine, or the outside flap has stuck shut with dust and cobwebs, the moisture backs up inside and the load won't dry. Common in flats where the hose run is long or looped.
A lint-clogged condenser / heat exchanger and a full water tank (condenser & heat-pump type)
Condenser and heat-pump dryers don't vent outside — they condense the moisture into water collected in a tank. If that tank is full, many models stop drying or flash a warning. There's also a sponge filter / heat exchanger lower down that has to be rinsed clear of lint — if it clogs, the air can't cool, so it can't condense, and the load stays wet.
Overloading or very wet washing (a weak spin from the washer)
If you cram the dryer past its capacity, the hot air can't tumble around each item, so drying is uneven and slow. And if your washing machine spins weakly (a low spin setting or a tired motor), the load goes into the dryer soaked — meaning the dryer has to do the washer's job too, and the cycle doubles.
A failed heating element, thermal fuse or thermostat
If the dryer tumbles normally but the washing comes out cold and wet with no heat at all, the heating element has usually burned out, the thermal fuse has blown (often because of an earlier vent blockage!), or the thermostat has failed. These are mains 220V parts and a job for an appliance technician.
Fix it — step by step
- Clean the lint filter before every loadOpen the lint filter (usually in the door rim or just below the door — it pulls up by hand) and peel the lint layer off with your fingers. If the mesh is filmed over with fabric-softener residue, rinse it under the tap, brush it with a soft brush, and let it dry fully before refitting.Do this before every load, not every week. A clean filter shortens the cycle and directly reduces the fire risk.
- Unplug before any deeper checkIf you're going to open a cover, remove the water tank, or take out the heat-exchanger filter, pull the plug first. A dryer draws heavy current and you don't work on it while it's live.Give it a few minutes to cool if it's just been running — the drum and heating element stay hot.
- Empty the water tank and rinse the condenser filter (condenser/heat-pump)If yours is a condenser or heat-pump dryer, slide out the water tank and empty it — many models stop drying once it's full. Then open the lower hatch, pull out the heat exchanger / sponge filter and rinse it under water until all the lint is gone, and let it dry before refitting.Empty the tank after most loads — it fills faster than you'd expect, and the dryer eases off drying before it stops completely.
- Check and clear the vent hose and outside flap (vented type)Pull the dryer away from the wall and inspect the hose: it should run straight, not crushed or coiled. Detach it and clear the lint packed inside. Then go to the outside vent on the wall and check the flap actually opens when the dryer runs — it's often nested with dust or spiders.Keep the hose as short and with as few bends as possible. Every extra bend traps damp air and lengthens the cycle.
- Don't overload, and spin the washing well firstLoad a sensible amount — the washing needs to tumble freely, not packed tight. And before you move it from the washer, run a high spin cycle (1200 rpm or more if your machine allows) to pull out as much water as possible.Simple rule: fill the drum two-thirds at most. Two loads are faster and cleaner than one crammed load that takes two hours.
- Give it airflow and space around itA dryer needs air around it — don't box it into a closed cupboard or wedge it into a corner with no ventilation, especially a heat-pump type that pulls in room air. Leave clearance behind and around the machine, and if the room is small and windowless, open the door during the cycle.In summer and high humidity (especially on the coast) a dryer naturally takes longer — that's not a fault. Ventilate the room.
- If it tumbles with no heat — make the callIf you've cleaned the filter, hose and exchanger and emptied the tank, and the load still comes out cold and wet with no heat, the problem is likely the heating element, thermal fuse or thermostat. Stop here and call an appliance technician.Tell the technician it 'tumbles with no heat' and that you've cleared the venting — it sends them straight to the element/fuse and saves you the diagnostic fee.
Tools & parts you'll need
When to call a professional
Call an appliance technician if: the dryer tumbles normally but produces no heat at all after you've cleaned everything (likely a heating element or thermal fuse); or it trips the breaker every time it starts; or it makes a knocking, grinding or burning smell. The heating element, thermal fuse, thermostat and motor are all mains 220V parts and technician work — don't open the rear electrical panel yourself. Above all: if you smell burning lint or see the dryer smoke, unplug it immediately and don't run it until a technician has checked it — built-up lint is a well-documented cause of house fires.
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Why does my dryer need two or three cycles to dry a load?
The usual cause is a clogged lint filter or blocked vent hose choking the hot air, so the moisture can't escape and the cycle just tumbles for nothing. Clean the filter before every load and clear the hose, and empty the water tank if it's a condenser type. The other common cause is overloading, or washing that goes in soaked because the washer spun it weakly — run a high spin first.
How real is the risk of lint actually causing a fire?
It's a real, well-documented risk. Lint is flammable, and when it builds up on the filter or inside the hose next to high heat, it can ignite. That's why you clear the lint filter before every load, clean the hose periodically, and don't run the dryer while you're out of the house or asleep. If you smell burning, unplug it at once.
What's the difference between vented, condenser and heat-pump dryers for drying?
A vented dryer pushes damp air outside through a hose — if the hose blocks, it fails. A condenser dryer turns the moisture into water in a tank you must empty, and has a heat exchanger that needs cleaning. A heat-pump is like a condenser but far more efficient, drying at a lower temperature (so it naturally takes longer) and needing airflow around it. All three lose performance if lint builds up.
The washing comes out very hot but still damp — why?
High heat with trapped moisture means the air is heating up but not leaving — that's a blocked airway (clogged filter, hose or exchanger) or a crammed load. The heat is there, but the moisture is stuck inside. Clear the whole air path. Excess heat also raises the fire risk, so don't ignore it.
It tumbles but with no heat and clothes come out cold and wet
This usually isn't a cleaning issue — most likely the heating element has burned out, the thermal fuse has blown (often because of an earlier vent blockage, so clear the venting too), or the thermostat has failed. These are mains 220V parts and a job for an appliance technician. Clear the air path first so the fuse doesn't blow again after the repair.