Radiator Noise When Heating Turns On

Short answer

Radiator noise when the heating turns on is usually caused by metal pipes and radiator panels heating up and expanding. This often produces clicking or ticking sounds and is usually normal. Louder noises such as banging or gurgling can indicate air, valve, or pressure issues that should be checked.

Why radiators make noise when heating turns on

When the heating switches on, hot water suddenly flows into pipes and radiators that may have cooled completely.

As this happens:

• metal pipes and radiator panels heat up quickly
• metal expands and moves slightly
• water flow increases through valves and bends

These rapid changes can create noticeable sounds, especially in systems that have been off for several hours.

What this noise usually sounds like

The sound you hear often points to the cause.

Clicking or ticking as heating starts

• Metal expanding as it warms
• Very common
• Usually harmless

Brief tapping sounds

• Pipes moving against floorboards or brackets
• Often settles quickly

Gurgling when heating starts

• Trapped air being pushed through the system
• Often fixable

Banging or knocking

• Water flow hitting closed or sticky valves
• Should be checked if loud

Is radiator noise when heating turns on normal?

In many homes, yes.

Usually normal if:

• The noise is brief
• It fades once radiators warm up
• Heating performance is normal

Not normal if:

• Noise is loud or violent
• Radiators heat unevenly
• Boiler pressure changes sharply
• The noise happens every time heating starts

Why this noise can be worse after the system has been off

Noise when heating turns on is often more noticeable:

• first thing in the morning
• after the heating has been off overnight
• during cold weather

Larger temperature differences cause greater expansion, which increases sound.

What to check first (in order)

Before assuming a fault, check these steps:

1. Listen to the sound type
   Clicking is normal; banging or gurgling needs attention.
2. Check boiler pressure
   Low or unstable pressure can exaggerate noises.
3. Bleed the radiator
   Trapped air often causes gurgling when heating starts.
4. Check radiator valves
   Valves opening suddenly can cause knocking.
5. Observe after warm-up
   Normal expansion noises fade once temperatures stabilise.

Why this is common in UK homes

Radiator noise when heating turns on is common in UK properties because:

• heating systems often cool completely overnight
• many homes use metal pipework
• pipes run through timber floors
• thermostatic radiator valves control flow room by room

These features make expansion sounds more noticeable.

When to get help

You should consider professional advice if:

• banging continues after warm-up
• multiple radiators are affected
• boiler pressure behaves unpredictably
• heating performance drops

Otherwise, occasional noise when heating turns on is usually normal.

Final reassurance

Radiator noise when heating turns on is usually caused by metal expanding and water beginning to flow again. As long as the noise is brief and radiators heat evenly, it is a normal part of how central heating systems behave.

Internal links to add

• Why Does My Radiator Make Noise at Night?
• Radiator Noise When Heating Turns Off
• Radiator Clicking or Ticking: Is It Normal?