The UK Government is replacing SAP with the Home Energy Model — a richer, evidence-led approach to assessing how homes actually perform. For housing associations, contractors, and retrofit coordinators, the direction of travel is already clear.
For years, EPC ratings and SAP calculations have provided a useful benchmark — but they have always relied on standard assumptions about occupancy and behaviour. The Home Energy Model changes the question.
SAP asks
“How should this property perform?”
HEM asks
“How is this property likely to perform under realistic conditions?”
The full rollout has been delayed to allow further testing, and SAP 10.3 will be used in the interim for Future Homes Standard compliance. But the Government has confirmed HEM is the long-term replacement for SAP. The themes are already established. Waiting for final implementation before preparing would be a mistake.
More sophisticated modelling of heat pumps, solar PV, battery storage, mechanical ventilation, smart controls, and modern insulation — based on realistic occupancy patterns and weather data, not simplified assumptions.
Poor insulation can no longer be hidden behind an efficient heating system. HEM properly distinguishes between inefficient buildings with efficient heating, and genuinely high-performing homes — supporting the fabric-first principle.
Improved modelling for air source heat pumps, ground source heat pumps, heat networks, solar generation, and smart energy management — giving designers and asset managers greater confidence in investment decisions.
Future homes won’t simply consume energy — they’ll actively manage it. Continuous monitoring, demand flexibility, smart tariffs, and behavioural engagement all become part of the assessment picture.
Asset databases alone will no longer be enough. Housing providers will increasingly need confidence in what’s actually happening inside their stock — not just what was designed to happen.
Future best practice will ask: did the intervention perform? Are tenants comfortable? Has energy use reduced? Has damp reduced? Are ventilation systems operating correctly? Delivery becomes continuous, not transactional.
Occupants influence heating patterns, ventilation, moisture, consumption, and comfort. Understanding how tenants interact with their homes — not to monitor individuals, but to ensure homes perform as intended — becomes a core function.
Future funding decisions will increasingly rely on measurable evidence. Organisations that can demonstrate real improvements will be better positioned for retrofit funding, decarbonisation programmes, and investment partnerships.
Clients will increasingly expect evidence that installations deliver expected outcomes. Simply installing equipment may no longer be enough.
Contractors may need to demonstrate completed works, commissioning, operational performance, post-installation verification, and customer outcomes — moving retrofit closer to performance contracting.
Future procurement is likely to reward contractors who can demonstrate quality assurance, installation evidence, performance monitoring, and independent validation — ahead of those who cannot.
Successful retrofit will increasingly require integration between housing providers, retrofit coordinators, designers, contractors, technology providers, and tenant engagement teams from the outset.
Evidence from a party independent of the retrofit delivery chain carries weight that self-certification does not — in funder submissions, in disputes, and increasingly in procurement scoring.
Increasingly, retrofit coordinators become the link between compliance, technical delivery, tenant engagement, quality assurance, and ongoing building performance. Rather than producing documentation at the end of a project, coordinators will increasingly oversee a continuous improvement process supported by evidence and monitoring.
The most successful retrofit projects will integrate compliance, delivery, engagement, and performance monitoring from the outset — not bolt them on at the end.
PAS 2035, BS 40101, future HEM methodology — the framework continues to evolve. Coordinators need partners who evolve with it.
An unbroken evidence record from pre-retrofit baseline through to post-retrofit verification — not a survey at the end.
Understanding how tenants interact with their homes, as an ongoing function of the coordinator’s role.
The future of retrofit isn’t about collecting more data — it’s about turning trusted data into meaningful action. The Continuous Property Health Audit does exactly what HEM is pointing towards: continuous, independent measurement of how homes actually perform, before and after retrofit, using data the property is already generating.
By combining independent monitoring, tenant engagement, and evidence-led reporting, housing associations and contractors can move beyond one-off assessments — understanding how homes perform after retrofit, identifying emerging issues before they escalate, and building the evidence base that future funding and compliance will require.
✅ The organisations best placed to succeed as regulation evolves will be those that can demonstrate — not simply assume — that their homes are healthier, more energy efficient, and delivering better outcomes for residents.
Continuous, independent, weather-corrected evidence from existing smart meters — built for the evidence-led future HEM is pointing towards.
Properties flagged by smart-meter screening receive IoT sensors — temperature, humidity, damp and mould risk, heat-loss anomaly detection, heating underperformance.
Usage visibility, green incentives, bill credit, and welfare protection — the tenant engagement layer HEM recognises as essential to real-world performance.
The baseline you create today is the evidence you’ll submit tomorrow. A short conversation is enough to understand what a pilot programme could generate for your organisation.
References: Home Energy Model: Future Homes Standard assessment — GOV.UK · Technical documentation — GOV.UK
