Cold Spots on Your Radiator? Here's the Fix
If your radiator is warm at the bottom but cold at the top, or if you hear gurgling and banging sounds when your heating is on, there's a simple explanation: trapped air. And the fix — bleeding the radiator — takes about five minutes and requires exactly one tool.
This is one of the easiest home maintenance jobs you can do, and doing it regularly can improve your heating efficiency by up to 15%. That means a warmer home and lower energy bills.
What You'll Need
- A radiator bleed key (under £2 at any hardware store)
- A small bowl or old cloth
- A towel nearby
Step 1: Turn Your Heating On
Switch on your central heating and let it reach full temperature. Walk around and feel each radiator. Any that are cold at the top need bleeding.
Step 2: Turn the Heating Off and Wait
Switch off your heating and wait 30 minutes. This prevents hot water from spraying you when you open the valve.
Step 3: Locate the Bleed Valve
The bleed valve is at the top corner of the radiator — it looks like a small square peg inside a round hole. That square peg is what your bleed key fits onto.
Step 4: Open the Valve
Hold your cloth beneath the valve to catch drips. Insert the bleed key and turn it anticlockwise — just a quarter turn. You'll hear hissing as air escapes. Keep the key in place and wait.
Step 5: Close When Water Appears
As soon as a steady trickle of water comes out, close the valve immediately by turning the key clockwise. Don't overtighten. The air is gone.
Step 6: Check Your Boiler Pressure
Bleeding radiators can drop your boiler's pressure. Check the gauge on your boiler (it should read between 1 and 1.5 bar when cold). If it's low, use the filling loop to top it up — your boiler manual shows how.
Step 7: Turn Heating Back On
Switch your heating back on and feel the radiators after 20 minutes. They should now be evenly warm from top to bottom.
How Often Should You Bleed Radiators?
Once a year at the start of autumn is the standard recommendation. But if you notice cold spots or hear gurgling at any time, bleed straight away.
Five minutes, one tool, a warmer home. That's what She Fixed is all about.