The Home Energy Model (HEM): What Every Homeowner, Builder and Developer Needs to Know in 2026

The UK building regulations are changing faster than ever — and at the centre of it all is the Home Energy Model (HEM). If you’re planning a new home, extension or conversion from 2026 onwards, you’ll soon be talking about HEM instead of the familiar SAP calculations you’ve used for years.

At sap2sbem.co.uk we are fully accredited Elmhurst Energy assessors with nearly 20 years’ experience and thousands of SAP & SBEM reports delivered across the UK. We’re already trained on both the current SAP 10.3 and the upcoming Home Energy Model, so we can make the transition completely seamless for your project.

Here’s exactly what the Home Energy Model means for you, why it’s a big step forward, and what you need to do right now.

Why is SAP being replaced by the Home Energy Model?

The Standard Assessment Procedure (SAP) has been the industry standard for decades, but it has limitations. It works with monthly averages and simplified assumptions that don’t always match how people actually use energy in modern homes.

The Home Energy Model (HEM) is a completely new, far more sophisticated simulation engine that:

• Models building physics hour-by-hour instead of monthly averages

• Gives realistic credits for modern technologies such as heat pumps, solar PV, battery storage and smart controls

• Produces much more accurate energy bills and carbon predictions

• Will eventually feed directly into future Energy Performance Certificates (EPCs)

In short, HEM is the calculation methodology that underpins the government’s Future Homes Standard — the plan to make all new homes zero-carbon ready.

Current timeline – what you need to know right now (April 20)

• Future Homes Standard Approved Documents were published on 24 March 2026.

• The Future Homes Standard technically comes into force on 24 March 2027 (with transitional arrangements until March 2028 for projects already in the system).

• SAP 10.3 remains the only approved methodology at launch (for a minimum of 3 months).

• The Home Energy Model becomes available at least 3 months after FHS launch.

• SAP 10.3 and HEM will then run in parallel for a minimum of 24 months.

• After the dual-running period, SAP will be phased out completely.

This phased approach gives everyone time to adapt – including us! We are already trained and fully prepared for both SAP 10.3 and the Home Energy Model. and can offer these as soon as they are live.

How HEM affects your new-build project

Aspect	Current SAP	New Home Energy Model (HEM)	What it means for you/your clients
Calculation method	Monthly averages	Hour by hour simulation	Far more accurate energy & running-cost predictions
Heat pumps & renewables	Simplified assumptions	Realistic modelling	Better credits for modern systems
Overheating (Part O)	Separate calculation	Separate calculation for now- possible future Integration	No change for now
Future-proofing	Good	Excellent	Homes ready for 2030+ carbon targets
EPC accuracy	Based on monthly data	Will feed directly into future EPCs	More trustworthy and realistic certificates

For commercial projects see our SBEM Calculations & BRUKL Reports page.

Do I still need a SAP calculation in 2026?

Yes – at launch. Until the Home Energy Model is fully approved and available, you (and your Building Control body) can and should continue using SAP 10.3 for compliance.

The moment HEM becomes live we will automatically offer both options and give you clear advice on which route is best for your specific project, budget and timeline.

Real benefits of the Home Energy Model for homeowners and developers

• Lower running costs — more accurate modelling means you’ll see the true savings from heat pumps and solar.

• Better design decisions — architects and developers can optimise glazing, insulation and ventilation in real time.

• Future-proof homes — properties that will easily meet tighter carbon targets in the 2030s.

• Higher property values — buyers and tenants increasingly want low-energy, low-bill homes with credible certificates.

Why choose sap2sbem.co.uk for your HEM or SAP assessment?

• Fully accredited by Elmhurst Energy

• Fast turnaround — most reports delivered in 3–5 working days

• Competitive pricing from £150 (new-build SAP) / £220 (SBEM)

• Over 10,000 assessments completed nationwide

• Clear guidance through the entire Future Homes Standard transition

• Friendly, expert team that explains everything in plain English

Whether you need a new-build SAP, SBEM, Part O overheating, or a full Home Energy Model assessment, we’ve got you covered. Find out more about our professional team here, or read what others are saying in our google reviews.

Whether you need a new-build SAP, SBEM, Part O overheating report, or a full Home Energy Model assessment, we’ve got you covered.

Read what our clients say in our Google reviews or find out more about our professional team here.

Ready to get your project Future Homes Standard compliant?

Get an instant quote for SAP / SBEM / HEM calculations → Or call 07800 654321 and we’ll explain exactly which route is right for you — in plain English, with no jargon.