If your radiators feel cold at the top or aren’t getting warm, they might need bleeding.
Due to the nature of the air, pockets can enter your central heating system and cause issues.
The air often collects at a point furthest from the boiler, which causes your radiator to be both noisy and cool, even when the heating is turned on.
I am absolutely bloody freezing 🥶 I have a massive thick jumper on, socks and leggings and I'm still cold ❄️ apparently this can be an effect of mounjaro and maybe because I am losing weight and my body feels it more. Not much fat to insulate with anymore lol 🤣 pic.twitter.com/gQ1JlP8GhE
— Newt (@newt_kiters) October 27, 2025
What tools do I need to bleed a radiator?
According to Checkatrade , just a radiator key. This should cost no more than £3 (don't worry if you don't have one).
How to bleed a radiator:
Step 1: Gather up the tools you’ll need
A radiator bleed key
Step 2: Make sure the heating is turned off
It’s important to do this before you start, as you don’t want any scalding water to drip onto your hands during the next steps. If you’ve recently had the heating on, wait at least two hours for everything to cool down.
Step 3: Put down a towel
Put a towel down under your radiator to collect any water that may drip out, or you can use a bucket if you prefer.
Step 4: Turn the valve
Use your radiator key to turn the valve. This is usually located in one of the corners.
When you come to do the task, you might discover you can’t find the radiator bleeding key.
Luckily, you can use a few alternative tools to get your radiators up to full heat again.
You will hear trapped air escaping – it will make a hissing sound.
Step 5: Wait until you see liquid
Keep the valve open until the hissing stops and you start to see water dripping out, then tighten it up again.
Step 6: Test it
Put your heating on for a few minutes to test if your efforts have paid off. Your radiators should be warm throughout, with no cold patches.
Recommended reading:
How to bleed your radiators to save money on energy bills
When should I turn my heating on? Expert advice to save money
Energy bills: Is it cheaper to leave the heating on all day?
How do I bleed a radiator without a key?
A bleed valve is shaped to make it easy to bleed without expensive tools. A radiator key is very cheap, often under £5.
However, if you can’t find one of these, something as simple as a flat-head screwdriver will suffice.
Find the small gap in the middle of the bleed valve and turn it the same way you would using a wrench or radiator key.
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