EPC reform is putting hot water under the spotlight, and water-efficient showers have never mattered more
Energy Performance Certificates (EPCs) in England and Wales are changing.
From 2026, EPC assessments are expected to transition to the Home Energy Model (HEM), a methodology designed to better reflect how homes and buildings actually perform, the energy they use, and their real running costs
At the centre of these reforms is a shift away from theoretical scores and towards real-world energy demand, including the energy used to heat water. For homeowners, housebuilders and retrofit professionals, this brings water efficiency and shower performance firmly into focus.
What’s changing and when?
EPCs will be generated using a methodology called the Home Energy Model (HEM), replacing the current SAP and RdSAP approaches. HEM uses more detailed modelling to assess energy use over time, providing a clearer picture of how buildings perform in everyday use.
Rather than relying on a single headline rating, new EPCs will present clearer performance metrics, including heating and hot water efficiency and estimated running costs. Government consultation is underway, with new EPC methodology expected to be introduced in late 2026, alongside a transition period where current ratings remain visible.
Crucially, this new approach places greater emphasis on ongoing energy demand, particularly the energy required to heat water for daily activities such as showering.