Dishwasher not heating? Why the water's cold and dishes stay wet

If your dishes come out cool and greasy, or the plastics are still soaking at the end, the dishwasher probably isn't heating the water. Not heating or drying is around 15% of our recent dishwasher repairs. Here's what's doing the heating and what tends to go.

How a dishwasher heats

Most machines no longer have a visible element in the base. The water is heated as it's pumped round, by a flow-through heater built into the circulation pump, or on a lot of Bosch and Neff machines by the heat pump that also handles the drying. Worth knowing, because it means "not heating" often points at the same assembly whether the complaint is cold water or wet dishes.

Rule these out first

A cold or eco cycle that runs cooler can look like a heating fault, so check the programme before anything else. And poor drying on its own, with the water clearly hot, is often just low rinse aid rather than a heating problem, so top up the rinse aid and see if it clears.

When it's a fault

If it's genuinely not heating, the flow-through heater or heat pump assembly has usually failed, and it's one of the parts we replace on dishwashers. A faulty thermostat, or the sensor that tells the board the water temperature, can do it too. They need testing to tell apart.

What a repair costs

Our band for a heating or drying fault is £95 to £160, with any parts quoted separately and the price confirmed before work.

Book a dishwasher repair

If the programme's right and the rinse aid's topped up and it's still not heating, book a dishwasher repair or find your local dishwasher engineer.

Frequently asked questions

Why is my dishwasher not heating the water?

On most machines the water's heated by a flow-through heater in the circulation pump, or a heat pump. When it genuinely isn't heating, that assembly, or a thermostat or temperature sensor, has usually failed.

Why are my dishes still wet at the end?

Either poor drying from low rinse aid, which is an easy fix, or a real heating fault so the final hot rinse never happens. Top up the rinse aid first to rule it out.

Does a dishwasher have a heating element?

Older ones had a visible element in the base. Most modern machines heat the water as it circulates, through the pump or a heat pump, so there's no separate element to see.

How much does it cost to fix?

£95 to £160 for a heating or drying fault, with any parts quoted separately and confirmed first.