How to Replace a Radiator (UK DIY Guide)
Replacing a radiator can improve heating efficiency and modernise a room. While many confident DIYers can complete this job safely, it involves draining part of your heating system and careful pipe alignment.
This step-by-step UK DIY guide explains how to replace a radiator safely and when professional help is recommended.
Tools You’ll Need
- Adjustable spanner
- Radiator bleed key
- Pipe wrench
- Drill and wall plugs (if repositioning brackets)
- Spirit level
- Bucket and towels
Materials Required
- New radiator
- Radiator brackets
- PTFE tape
- Radiator valves (if replacing)
- Inhibitor (recommended)
Step 1: Turn Off the Heating
Switch off your boiler and allow the system to cool completely.
Turn off both radiator valves by rotating clockwise.
Step 2: Drain the Radiator
Place a bucket under the valve.
Use a spanner to loosen the valve nut carefully.
Open the bleed valve to allow air in and water to drain out.
Allow the radiator to empty fully.
Step 3: Remove the Old Radiator
Lift the radiator off the wall brackets.
Tilt slightly to drain any remaining water into the bucket.
Remove old brackets if replacing.
Step 4: Install New Brackets
Measure and mark the correct height.
Use a spirit level to ensure brackets are straight.
Drill holes and secure brackets firmly.
Step 5: Fit the New Radiator
Wrap PTFE tape around valve threads.
Mount the radiator onto brackets.
Reconnect valves and tighten securely.
Ensure all connections are aligned properly.
Step 6: Refill and Bleed the System
Turn the valves back on.
Repressurise the boiler if needed (for combi systems).
Use the bleed key to release trapped air.
Check for leaks around all connections.
Common Mistakes to Avoid
- Not allowing the system to cool
- Forgetting PTFE tape on threads
- Overtightening fittings
- Installing brackets out of level
- Forgetting to add inhibitor
Poor installation can lead to leaks or uneven heating.
When to Call a Professional
You should contact a heating engineer if:
- Pipework needs altering
- You are replacing with a different size radiator
- You are unsure how to repressurise the boiler
- There are persistent leaks
- The system contains sludge or corrosion
See our Heating & Boiler Repair Cost Guide for typical UK pricing.