What do the tumble dryer settings actually mean?

Dryer programmes differ in heat and in how they decide when to stop — and using the wrong one is the main cause of shrinkage, creasing and damaged elastic.

Difficulty: beginner
Time: 10 min
Read: 4 min

Short answer

Use low heat for almost everything and accept it takes longer. Sensor programmes stop when the load is dry; timed programmes run regardless and over-dry. Cupboard dry is fully dry, iron dry leaves it damp on purpose. Anything with elastane, and anything you care about, goes on low.

Almost all clothing damage attributed to tumble drying is heat damage. Cotton shrinks, elastane degrades, synthetics pill and adhesives fail. The dryer's own settings are the control for this, and most people use one programme for everything without knowing what the others do.

What you'll need

A tumble dryer
The care labels on what you are drying

The five families of UK care label symbol

Step by step

Read the dryer symbols on the label.A circle in a square means tumble drying is allowed. One dot inside means low heat, two means normal. A crossed-out square means do not tumble dry at all.
Understand the difference between sensor and timed.Sensor drying measures the moisture in the load and stops when it is dry. A timed programme runs for the time you set regardless, which is how clothes get over-dried and cooked.
Use sensor programmes wherever the machine offers them.They are gentler and cheaper, because they stop as soon as the job is done rather than running on with a dry load tumbling in hot air.
Know what the dryness levels mean.Iron dry leaves the load deliberately damp so it presses easily. Cupboard dry is ready to put away. Extra dry over-dries, and is only for very thick towels.
Use low heat as the default.It takes longer and costs marginally more per load, and it eliminates most shrinkage, most creasing and most elastane damage. It is the right default for everything except towels.
Dry similar items together.Mixing towels with T-shirts means either the towels are damp or the T-shirts are baked. Sensor programmes work poorly on mixed loads for the same reason.
Do not overfill it.A dryer needs air to move through the load. More than about two thirds full and nothing tumbles, drying takes twice as long and everything comes out creased.
Use the anti-crease or cool-down phase.It tumbles without heat at the end so the load does not sit hot and set into creases. If your machine has it, it is free ironing avoidance.
Take the load out immediately.Warm clothes left in a stationary drum set every crease they are lying in. This causes more ironing than anything the dryer itself does.
Clean the lint filter every single load.A blocked filter makes the machine run hotter and longer, which is both a fire risk and the cause of a lot of heat damage.

Tips

Wool dry programmes are gentle tumbling with almost no heat, intended for airing rather than drying. They will not dry a wet jumper and should not be asked to.
Dryer balls genuinely reduce drying time by keeping the load open, and they replace dryer sheets, which coat fabric the way conditioner does.
A load spun at 1400 rather than 1000 in the washer arrives with much less water and takes noticeably less time and energy to dry.

Common mistakes

Using high heat for everything — Heat is what shrinks cotton, destroys elastane and delaminates coated fabrics. Low heat costs slightly more per load and saves far more in clothing.
Setting a timer rather than using the sensor — A timed cycle keeps running after the load is dry, tumbling hot dry fabric against itself. That is what causes pilling, shrinkage and static.

If it doesn't work

Clothes come out very creased

Cause: Overloaded, no cool-down, or left in the drum — Fix: Reduce the load, use the anti-crease phase, and unload immediately while items are still slightly warm.

Load still damp after a full cycle

Cause: Blocked filter, full condenser, or an overfilled drum — Fix: Clean the lint filter and condenser unit, and dry no more than two thirds of a drum at a time.

Everything is full of static

Cause: Synthetics over-dried — Fix: Use a sensor programme, take the load out slightly damp, and use dryer balls rather than sheets.

T-shirts have shrunk

Cause: High heat and over-drying — Fix: Not reversible. Use low heat and remove at iron-dry rather than extra-dry.

Questions people ask

Is a lower heat setting cheaper to run?

Roughly the same overall, sometimes slightly more, because it runs longer. The saving is in the clothes rather than the electricity.

Can I dry things labelled do not tumble dry on low?

Sometimes it survives, but the label is there because of shrinkage, coatings or elastic. Wool, silk, waterproofs and anything with a rubberised backing genuinely should not go in.

Why does the machine take longer than the display says?

Sensor programmes estimate at the start and correct as they go. A heavier or wetter load than expected, or a partly blocked filter, extends it.