How to bleed a radiator in five minutes

If a radiator is cold at the top and warm at the bottom, there’s air trapped in it. Letting it out takes five minutes and a radiator key, which costs about £2.

1. Turn the heating off and let the radiators cool, so you don’t get a face full of hot water.
2. Hold a cloth under the valve at the top corner of the radiator.
3. Turn the key a quarter turn anticlockwise. You’ll hear a hiss as the air comes out.
4. Close it when water appears, a steady trickle rather than spits.
5. Check the boiler pressure. If it’s dropped below 1 bar, top it up (your boiler’s manual shows how).

If it’s still cold after bleeding, or you’re bleeding it every week, there’s a bigger problem: send me a message.