If the top of your radiator feels cooler than the bottom, then it probably needs bleeding to get rid of any trapped air inside. This process only takes 10 minutes and can be done in 5 easy steps.

Before you begin, check that you have a bleed key that fits your valve. This is usually located at the top of your radiator. You will also need a cloth and a bowl to catch any drips.

Radiator Key


STEP 1 : Fully open any thermostatic radiator valves and run your central heating for ten minutes. After this, turn off the system.

Radiator Valve

STEP 2: Put the bleed key into the valve and slowly turn anticlockwise. Be alert and make sure you have your cloth ready to shield your hand. Keep a small bowl or cup below the valve to catch any small drops of water.


STEP 3: If there is trapped air, you should begin to hear a hissing sound as it is released. As soon as water begins to drip out, close the valve.

STEP 4 : Check the rest of your radiators. Often trapped air will only occur in one or two.

STEP 5 : Once finished, turn the heating back on and check each radiator to ensure there are no drips.



  • You should bleed radiators at least once a year to release any trapped air.

  • If you notice that the radiators in one area of your house are cooler than the others, then your radiators aren’t properly balanced. You should call a tradesman to fix the problem to ensure your radiators are providing balanced to heat your home.