Why are my pipes noisy when the heating comes on?

Question

What is causing this to happen? I think it's 100% worse than it was last year when we started having the heating on more

Saulius · Answer

As hot water flows through, copper pipes expand in length. If they are tight against floor joists, wooden beams, or plasterboard, they will make loud creaking, tapping, or knocking sounds as they rub against these materials.
Loose Pipework (Rattling)
Air in the System (Gurgling/Clicking)
Water Hammer (Loud Banging)
Why it's worse than last year. You using heating mo often.
Steps to reduce noise.
Bleed Your Radiators: This is the first step to remove air trapped in the system.
Check Boiler Pressure: Ensure it is between 1 and 1.5 bar. If it's too high or low, it can cause noise.
Use Inhibitor: Add central heating inhibitor to the system to reduce future corrosion and sludge buildup.

Christopher · Answer

I see this all the time when a heating system kicks in and temperatures jump from cold to 60-70°C. If your pipes are making a racket.

But it also could be:

Copper Expansion (The 'Tapping' or 'Creaking')
This is the most frequent culprit. Copper pipes physically grow in length as they heat up. If your installer notched them too tightly into your floor joists or used cheap plastic clips without any 'give,' the pipe will rub against the wood or plastic as it expands. That friction creates those rhythmic clicking or groaning sounds you hear in the floorboards.

Trapped Air (The 'Gurgling' or 'Sloshing')
If it sounds like there’s a waterfall behind your walls, you’ve got air in the loop. Air is a gas and moves differently than water; it gets stuck in high points or 'loops' in the pipework. Not only is it noisy, but it also makes your pump work harder and stops your radiators from getting hot at the top. You can usually fix this by bleeding your radiators to release the pressure.

Debris and Kettling (The 'Whistling' or 'Banging')
If the noise sounds like it’s coming from the boiler itself—similar to a kitchen kettle reaching a boil—we call that 'kettling.' Over time, 'sludge' (rust and minerals) builds up on the heat exchanger. This creates hotspots where water flashes into steam bubbles and then collapses, causing a loud banging or whistling. This usually requires a professional system flush to clear the 'gunk' out.

High Pump Speed (The 'Constant Hum')
Sometimes the internal pump is simply set too high for the size of your house. If the water is being forced through the narrow copper pipes too fast, it creates a constant vibrating hum or a 'whooshing' sound. We can usually solve this by just turning the pump speed down a notch.

My Advice: If the noise is just a few clicks when the heat starts, it’s usually just expansion and nothing to worry about. However, if you're hearing heavy banging or constant gurgling, it’s worth getting it checked by an engineer.

Why are my pipes noisy when the heating comes on?

Follow Us

Cookies

Manage Cookies

Essential cookies

Analytics & Tracking

Advertising