‘I’m a plumbing engineer - people don’t know what the numbers on their radiators mean’

‘I’m a plumbing engineer - people don’t know what the numbers on their radiators mean’ (Image: Getty)

Heating can quickly escalate your energy bills and cause many problems in homes.

Many people turn their radiator knobs when the cold weather strikes, without really understanding what those little numbers mean.

That contraption on your radiator is a thermostatic radiator valve (TRV). Understanding its workings could be a nifty financial hack for people looking to slash their energy bills. 

True, not all radiators come equipped with one, but for those that do, the valve can be a game-changer in controlling or outright stopping the surge of hot water into the radiator.

Nathan Martin-Nicholls from In House Plumbing and Heating often encounters customers questioning the figures on the radiator dial.

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Not all radiators come equipped with one of these valves (Image: Getty)

Most customers wrongly reckon these numerals correspond to the heat emanating from the radiator, but that’s a total misconception.

Nathan told The Sun: “The numbers actually relate to the temperature in the room, not the temperature of the radiator.”

A TRV susses out the ambient temperature in a space and controls the amount of hot water that needs to flow into the radiator accordingly.

A TRV controls the amount of hot water that needs to flow into the radiator accordingly (Image: Getty)

This clever device will clock if a room is too cold and give the go-ahead for more hot water to flow through the radiator.

It’s also sharp enough to sense if a zone is toastier and constricts the hot water flow, ensuring the room’s warmth stays consistent.

The figures on the TRV should generally match the room’s temperature. For instance:

0 = 0C (off)

✱ = 7C (typically represented by a snowflake symbol or full stop)

1 = 10C

2 = 15C

3 = 20C

4 = 25C

5 = 30C

Nathan highlighted that TRVs' primary advantage is their potential to help Brits cut down on heating expenses when utilised properly.

British Gas suggests that households could pocket savings of up to £75 annually if they have TRVs installed.

For those who have a room thermostat, they do not need a thermostatic radiator valve.