Which? published research on 23 September 2025 finding that an overwhelming three quarters (75%) of homeowners surveyed with an older heating system are not prepared in the event they should need to replace their boiler, with a quarter (27%) of them taking a "wait until it breaks" approach1. The consumer organisation is encouraging businesses and the government to help consumers plan for boiler breakdowns1.
The study draws on two surveys conducted by Yonder on behalf of Which? between 13 and 17 June: one of 938 homeowners with a heating system aged eight years or more, and one of 1,077 homeowners who had replaced or upgraded their heating system in the previous two years1. It found that failing to plan doubles the chances of needing an emergency replacement (39% compared with 19%)1. Homeowners who did not prepare were twice as likely to struggle to find an installer (15% compared with 8%), and nearly three times as likely to wait more than a day for a replacement heating system (63% compared with 22%), with the most common wait being two to three days (28%)1. Among those who had planned ahead, the majority (73%) were resolved in under 24 hours1.
On servicing, 60% of homeowners surveyed have their boiler serviced once a year as recommended, seven per cent say they never have their boiler serviced and a further 31 per cent do so less than once a year1. One in five (17%) reported their heating systems were not working well, yet over half (53%) had not made any preparations to replace them1. Over two thirds (68%) of homeowners surveyed with older boilers had not been given any information on when or how to replace their heating system, including from a heating engineer1. Only a fifth (22%) of homeowners with older heating systems had taken steps to plan for a future replacement1.
On replacement choices, 76% of homeowners surveyed would opt for a like-for-like gas boiler replacement and 15% were considering a heat pump1. Those who planned ahead were twice as likely (21% compared with 11%) to consider different heating options, with nearly a quarter (24%) exploring a heat pump when replacing their boiler1. Just under half (44%) said they would consider a heat pump, rising to 85% among those who came across information during their research1. Six in ten said they could not get a heat pump installed quickly enough, and concerns about upfront costs and reliability persist1.
Homeowners who planned their upgrade tended to spend £500 more on average (£3,000) than those who did not (£2,500)1.
"Our research shows that too many households are unwittingly leaving themselves vulnerable to boiler breakdowns, often resulting in emergency call outs to installers during the coldest and busiest time of the year."
Why it matters for households
A boiler that fails without warning leaves a home without heating or hot water, and the research links that position to longer waits, more difficulty finding an installer and a rushed decision made under pressure1. Households that plan ahead, by contrast, were more likely to have a replacement resolved within a day and more likely to weigh up more than one heating option1. The findings also suggest that the information a household encounters shapes what it considers: the share willing to consider a heat pump rose from 44% to 85% among those who came across information during their research1. What a replacement costs varies with the approach taken, with planned upgrades averaging £500 more than unplanned ones in the survey1. Which? notes that planning an upgrade presents an opportunity to carry out additional tasks such as flushing out radiators1. The cost of a new boiler is one of the practical factors a household weighs, alongside the wider question of how a home is heated, which sits within our boilers and heating coverage.
What happens next
Over the next months, Which? will be using awareness campaigns to encourage consumers to plan ahead, running social media messages in early Autumn and early Spring, and will share lessons from those campaigns with other stakeholders1. The organisation says it is grateful to the MCS Foundation for supporting some of the research and marketing activities in this project1. No government response to the findings has been reported.