HEM:EPC wrapper
The HEM:EPC wrapper refers to a software component being developed by the UK government to translate the technical output of the new Home Energy Model (HEM) into official Energy Performance Certificates (EPCs) for new and existing homes. It functions as a specialised layer that defines inputs, applies standardised assumptions, and converts raw data into EPC ratings and recommendations, replacing the current Reduced data SAP (RdSAP).
The wrapper sits around the core HEM engine, acting as a translator to produce EPCs. It specifically handles the calculation of new metrics for carbon, energy efficiency, and "smart readiness". Currently being developed this, it was still in consultation during early 2026, aiming at a full launch in 2025/2026. The principle of wrappers is to allow models to to carry detailed information but not require this for every application of the model but instead give the option for certain assumptions, balancing speed and accuracy. Another example of a wrapper is the FHS wrapper which the Future Homes Standard (FHS) wrapper, meaning it is to be used for building regulation compliance, once the FHS becomes standards.
[edit] Related articles on Designing buildings
- Air permeability testing.
- Air tightness.
- Applying Fabric First principles: Complying with UK energy efficiency requirements FB 80.
- Approved building energy calculation software.
- Approved documents.
- Are Energy Performance Certificates accurate?
- Building Regulations.
- Building Research Establishment.
- Changes in SAP 10.
- Co-heating test.
- Conventions for U-value calculations (2006 edition) BR 443.
- Dynamic Simulation Model.
- Emission rates.
- Energy efficiency of traditional buildings.
- Energy Performance Certificates.
- Energy Performance of Buildings Directive.
- IHBC responds to Energy Company Obligation ECO4 and PAS 2035.
- National Calculation Method.
- Passivhaus vs SAP.
- Standard Assessment Procedure SAP.
- Simplified Building Energy Model.
- Target fabric energy efficiency rate.
- The Home Energy Model and Future Homes Standard assessment wrapper
- Thermal dynamic analysis.
- U-value conventions in practice: Worked examples using BR 443.
Featured articles and news
The first line of defence against rain, wind and snow.
Building Safety recap January, 2026
What we missed at the end of last year, and at the start of this...
National Apprenticeship Week 2026, 9-15 Feb
Shining a light on the positive impacts for businesses, their apprentices and the wider economy alike.
Applications and benefits of acoustic flooring
From commercial to retail.
From solid to sprung and ribbed to raised.
Strengthening industry collaboration in Hong Kong
Hong Kong Institute of Construction and The Chartered Institute of Building sign Memorandum of Understanding.
A detailed description from the experts at Cornish Lime.
IHBC planning for growth with corporate plan development
Grow with the Institute by volunteering and CP25 consultation.
Connecting ambition and action for designers and specifiers.
Electrical skills gap deepens as apprenticeship starts fall despite surging demand says ECA.
Built environment bodies deepen joint action on EDI
B.E.Inclusive initiative agree next phase of joint equity, diversity and inclusion (EDI) action plan.
Recognising culture as key to sustainable economic growth
Creative UK Provocation paper: Culture as Growth Infrastructure.
Futurebuild and UK Construction Week London Unite
Creating the UK’s Built Environment Super Event and over 25 other key partnerships.
Welsh and Scottish 2026 elections
Manifestos for the built environment for upcoming same May day elections.
Advancing BIM education with a competency framework
“We don’t need people who can just draw in 3D. We need people who can think in data.”