The Institution of Gas Engineers and Managers (IGEM) has published its response to the government consultation on the future Energy Performance Certificate methodology, dated March 2026. The body said it disagreed with the proposed design of the Heating System Metric and with the option of reserving the highest A and B scores for electric cooking appliances1.
The consultation, run by the Department for Energy Security and Net Zero (DESNZ), covers the Home Energy Model, the replacement for the SAP methodology behind EPC regulations and reform. IGEM answered questions nine and 11. On question nine it said preventing any home with a fossil-fuel component from reaching a C rating or above "shifts the EPC from an emissions-based tool to a technology classification system"1.
"We support the aim of creating a more accurate and meaningful metric for consumers and policymakers. However, we are concerned that several elements of the proposed Heating System Metric risk pre-determining outcomes in favour of specific technologies rather than reflecting the real emissions performance of homes."
IGEM argued that carbon outcomes depend on the carbon intensity of the energy source, how a system is operated, appliance efficiency and the ability to integrate low-carbon gases. It cited evidence that biomethane already contributes significantly to UK energy supply and could grow to 120 TWh by 2050, and that hybrid systems can cut gas consumption by up to 80%1. It said the proposed cap holding hybrid systems to a D rating does not reflect real-world performance, and that hybrids provide the lowest-cost clean heat routes for the 30 to 47% of low-efficiency homes through bio-hybrid configurations1.
On affordability, IGEM cited figures that 16% of UK adults have no savings and 39% have £1,000 or less, and that the average cost of installing an air source heat pump is around £13,0001. On question 11, it said cooking is typically less than 10% of household energy demand even in efficient homes, and that reserving A and B bands for electric cooking would over-weight a low-impact area, create cost burdens such as re-wiring when kitchens are replaced, and narrow consumer choice. It also noted NHS guidance that people with pacemakers are advised to keep 2ft from induction hobs because of electromagnetic interference risks1.
IGEM's recommendations to DESNZ were: a performance-based, technology-neutral methodology rooted in measured or dynamically modelled carbon outcomes; removal of blanket rating caps for hybrid systems; integration of green-gas pathways across the methodology; no over-weighting of cooking appliances; and reflection of whole-system impacts such as peak-shaving and avoided infrastructure costs in the Heating System Metric1.
Why it matters for households
An EPC rating affects how a home is described when it is sold or let, and increasingly which upgrade measures are expected of it. The dispute is about whether that rating should follow the carbon the home actually emits, or the technology installed in it. Under the proposals IGEM describes, a home with any fossil-fuel component could not reach a C or above, and a hybrid system could not score above a D, regardless of measured emissions. IGEM's position is that this would penalise homes using green gas tariffs or hybrid setups that cut gas use, and would push households towards higher-cost work. For a household weighing up a heat pump, a hybrid system or a green gas tariff, the methodology decides whether that choice is reflected in the rating at all. The consultation outcome has not been reported.
What happens next
No decision or timetable has been reported. The consultation sits within the wider energy consultations and how policy is made process run by DESNZ, and further detail on the regulation and policy framework has not been published.