Bleeding radiators before winter sets in could help households save around £100 in wasted energy over a heating season, according to heating experts Your NRG. The simple maintenance task releases trapped air that stops hot water from circulating properly, forcing the boiler to work harder and increasing energy use.
Why trapped air drives up costs
Your NRG explains that trapped air prevents hot water from circulating efficiently, meaning the boiler must pump harder and longer to heat a room. A spokesperson said: "If there is air in your radiators, the hot water cannot circulate properly. That inefficiency means your boiler must pump harder and longer, increasing your energy use and costs."
Cold spots near the top or centre of a radiator can indicate that air needs to be released. According to Your NRG: "A radiator with air in it may feel cold in the centre or at the top. Bleeding removes that air and allows heat to spread evenly across the entire surface."
Your NRG estimates that an average household could waste around £100 worth of energy over a heating season if radiators are left unbled, although the amount depends on the size of the home and how much heating is used. Its spokesperson said: "For an average household, the extra energy wasted over a season due to unbled radiators could amount to around £100, depending on the size of your home and your heating usage."
How to bleed a radiator safely
Energy Saving Trust guidance also highlights how trapped air can reduce radiator efficiency, while Citizens Advice recommends checking radiators annually, preferably before colder weather arrives. Before starting, switch off the heating and give the radiators time to cool down.
Your NRG advises using a radiator key to open the bleed valve gently, allowing trapped air to escape. Its spokesperson said: "Turn off your heating first and wait for the radiators to cool. Use a radiator key to open the bleed valve gently until air hisses out."
Once water starts to emerge, close the valve carefully and check the boiler pressure. Citizens Advice advises households to understand how to repressurise their system before bleeding radiators and to consult the boiler instructions if they are unsure.
Your NRG added: "You might need to top up your system pressure after bleeding. If in doubt, get professional help but for most households this is a simple job that pays for itself many times over."
Impact on household bills
Although the estimated £100 saving is not guaranteed, keeping radiators in good working order could help households avoid unnecessary energy use throughout the colder months. It comes after Ofgem increased the energy price cap by 4 per cent on October 1, taking the typical annual bill for households paying by Direct Debit to £1,723.
