The Department for Energy Security and Net Zero announced on 14 March 2024 that the Clean Heat Market Mechanism would be delayed to 1 April 2025, alongside changes to the Boiler Upgrade Scheme1. The announcement was made by Claire Coutinho, Secretary of State for Energy Security and Net Zero, and was described by MCS as "some significant changes to UK heating policy"1.
Under the revised Boiler Upgrade Scheme eligibility rules, homeowners will no longer need to install cavity wall or loft insulation to access the grant1. The scheme will also accept biomass boilers with integrated cooking functions, which MCS said its own Biomass Standard already covers1.
Ian Rippin, chief executive of MCS, said the changes answered the certification body's calls for a broader choice of low carbon heating:
MCS said heat pump installations had reached record numbers so far in 2024, and repeated the government target of installing 600,000 heat pumps a year by 20281. The announcement did not set out new funding levels for the grant, and no figure for the value of individual vouchers appears in the material published alongside it1.
| Change | Detail |
|---|---|
| Clean Heat Market Mechanism start date | Moved to 1 April 20251 |
| Boiler Upgrade Scheme insulation condition | Cavity wall or loft insulation no longer required to access the grant1 |
| Biomass eligibility | Biomass boilers with integrated cooking functions now eligible1 |
Why it matters for households
The insulation condition had tied grant access to a second, separately funded improvement for some homes. Removing it means a household whose EPC recommends loft or cavity wall insulation is no longer blocked from applying on that ground alone, although the practical case for insulation before or alongside a heat pump is unchanged, as MCS itself notes1. Homes that already have a gas boiler remain a separate question under the scheme's rules, and the announcement does not alter the general position on fossil fuel heating.
For off-gas-grid homes, the biomass change widens the range of appliances that can be supported, including units that also cook. That matters where a single appliance serves both heating and cooking, a common arrangement in rural properties without a mains gas connection. The delay to the Clean Heat Market Mechanism, which was designed to place obligations on heating manufacturers and importers rather than on households, pushes its effect on the boiler market back by a year1.
What happens next
The Clean Heat Market Mechanism is now due to start on 1 April 20251. The revised Boiler Upgrade Scheme rules take effect under the 14 March 2024 announcement, and MCS said it expects the changes to open the grant to more consumers1. No further dates were given for the scheme's administration or for any review of grant levels1.
Sources1 cited
- MCS responds to key changes to the Boiler Upgrade Scheme - MCS, mcscertified.com