Research has found that a fifth of UK homes have a boiler more than 10-years-old and an estimated 1.3 million households have run their boiler for more than 20 years.
This means that they were installed before the first iPhone was released, the rise in social media and old enough to have outlasted eight Prime Ministers.
The findings from HomeServe also revealed that 28% of UK households admit they plan to wait until their boiler completely breaks down before replacing.
While 27% put off replacing their boiler due to cost, HomeServe has warned that running old boilers could be costing the nation £1bn.
The company said cost is a primary driver behind delayed boiler replacements, as 27% of homes reported that they simply cannot afford one. However, HomeServe noted that running a boiler which is more than 10-years-old can cost households an estimated £202 per year in lost efficiency, which could add up to £1bn nationally.
The research also showed that 34% of those with a boiler have experienced it making strange noises. A total of 11% reported humming, seven per cent cited gurgling and six percent noted vibrating. HomeServe said these sounds can be a warning sign of age and inefficiency.
This comes at a time when callouts for noisy boilers are shown to increase by 14%, it noted, as systems are pushed harder during the colder months.
The findings revealed that 17% said the constant whirring and banging puts them “on edge” in their homes, whilst 11% are being kept awake at night by the sound of their heating system.
Chris Houghton, gas expert at HomeServe, said: “Many homeowners only act once a boiler fails completely, but by that point the damage is already done.
“With older boilers more prone to inefficiency and breakdowns, and in some cases a lack of parts availability due to age, we want to help highlight the risks and give households the chance to have potential problems spotted early, saving money on efficiencies and also avoiding an expensive surprise at a time when you need your boiler the most.”