The government announced in March 2024 that it would delay the Clean Heat Market Mechanism, with a new proposed implementation date of April 20251. The scheme would have required boiler manufacturers to make heat pumps at least 4% of their sales, with a £3,000 penalty for each missed heat pump installation1.
Ahead of the original start, in January 2024, a number of boiler manufacturers including Baxi, Glow-worm, Ideal, Vaillant and Worcester Bosch raised the wholesale price of each boiler they sold by between £95 and £120, or £114 to £144 including VAT, in response to the proposed scheme1. The increase was described by some as a "boiler tax"1.
After the delay was announced, several of the companies said they would return the money. Worcester Bosch told Which? it had added £120 to the cost of each boiler sold to a merchant customer between 1 January and 15 March 2024, and had since returned this in full to each customer1. Baxi, Ideal and Vaillant did not respond to requests for comment1. Wolseley, a distributor selling to traders, said it had refunded 99% of its customers by 11 April, and that remaining customers who had paid in cash should get in touch with proof of purchase before 30 June to receive a full refund1. BOXT, which sells directly to consumers, said it had frozen its prices in January 2024, so its customers had not had the extra cost passed on1.
Which? noted that because the money was returned voluntarily and not because of a product fault, it is not technically a refund and does not carry the same customer protections1. Whether a householder is owed anything depends on whether their installer passed the extra cost on; Which? said that if a trader told a customer they were paying extra to cover the additional cost, the customer is within their rights to ask for it back1.
Why it matters for households
The mechanism was designed to shift the boiler market towards heat pumps by putting a cost on manufacturers that fell short of the 4% threshold1. Its delay means the sales pressure on manufacturers does not begin until April 2025 on the proposed timetable, and the price increases some of them applied in anticipation have been unwound through the supply chain rather than at the point of sale1. For a household, the practical effect is that any repayment depends on the installer, not the manufacturer, because boilers are typically bought by a tradesperson and then sold on1. The wider policy picture, including grant levels and installation targets, sits in the site's guide to UK heat pump policy, targets and the rules coming.
What happens next
The proposed implementation date is April 20251. Wolseley set a 30 June deadline for customers who paid in cash to claim a full refund with proof of purchase1. No further government timetable beyond the April 2025 date has been reported.
Sources1 cited
- 'Boiler tax' repayments explained - Which?, which.co.uk