If your radiator clicks when the heating turns on or cools down, it’s usually caused by movement inside the system rather than a fault. In most UK homes, clicking noises come from pipes expanding, valves adjusting, or air shifting as temperatures change — and they’re almost always harmless.
The timing of the noise matters. Clicking that happens just after the heating starts, or as the radiator cools, points to normal expansion rather than a boiler problem.
Pipes expanding against brackets or floor clips
This is the most common cause. As hot water flows into the pipes, the metal expands slightly. If the pipes are tight against joists, wall holes, or floor clips, that movement creates a clicking or tapping sound.
The noise often fades once everything reaches temperature, then returns again as the system cools down.
In my case, loosening the pipe clips slightly and adding a bit of padding where the pipes passed through the floor stopped the clicking immediately.
Thermostatic radiator valves can click as they adjust
TRVs contain moving parts that open and close as room temperature changes. When they react quickly — especially at the start or end of a heating cycle — they can produce a light clicking or tapping noise.
Removing the TRV head and refitting it properly often reduces this. If the pin underneath feels stiff, freeing it can also help.
Air moving inside the radiator
Small air pockets can shift when hot water enters the radiator, causing clicking or ticking sounds. This is more noticeable in radiators that don’t heat evenly.
Bleeding the radiator usually reduces this noise straight away.
If your radiator is also cold at the top, this behaviour is explained in Radiator Warm at Bottom but Cold at Top.
Why clicking is usually nothing to worry about
Unlike banging or loud knocking, clicking sounds are rarely a sign of damage. They don’t mean the radiator is failing or that the boiler is unsafe. They’re simply the result of metal reacting to temperature changes.
As long as the radiator heats normally and the noise doesn’t worsen over time, it’s considered normal behaviour.
What usually stops radiator clicking
In most homes, the noise fades once:
- pipes are slightly freed or padded where they pass through floors
- TRVs are reseated or freed
- air is fully bled from the radiator
After doing this, my system returned to normal — no late-night tapping, just quiet background heat.
How this fits into running your heating smoothly
Small noises are often early signs of airflow, balance, or expansion issues rather than faults. Addressing them early keeps the system running quietly and efficiently.
If you’re working through multiple heating issues or want a clear overview of how everything connects, this guide pulls it all together: How to Keep a UK Home Warm for Cheap.
