Energy and Calculations
Home Energy Model
The Home Energy Model (HEM) is the government's new method for calculating the energy performance of homes. It will replace SAP. It has not yet launched, and SAP 10.3 is currently the only approved method. This page explains the position on GOV.UK in plain English, and how we can help with SAP now and HEM when it arrives.
What is it? HEM is a calculation method for assessing the energy performance of homes. GOV.UK says it will replace the Standard Assessment Procedure (SAP), first published in 1993. Together with the Future Homes Standard 'wrapper', it makes up the HEM: FHS assessment used to show compliance.
Do you need one now? No. GOV.UK says SAP 10.3 is currently the sole approved methodology. The rules are still changing, so we keep this page under review and only state what GOV.UK says.
What does this mean for a housebuilder? For now, energy assessments for new homes still use SAP. What changes in March 2027 is the Part L standard itself, set out in the 2026 Approved Document. HEM is the calculation method that will sit alongside, and later replace, SAP.
Last reviewed:
Records supplied with Home Energy Model
Today you receive SAP 10.3 compliance reports for Building Control, design-stage before work starts and as-built at completion, plus the EPC. When HEM is introduced, we will set out on this page what changes in the reports and submissions, based on the GOV.UK guidance.(Source: GOV.UK: Standard Assessment Procedure; Approved Document L: Energy and greenhouse gas emissions (2026) (GOV.UK))
We will update this page as GOV.UK publishes new guidance, and the last reviewed date above shows when it was last checked against the official pages.
Coordinating project evidence for Home Energy Model
The GOV.UK Standard Assessment Procedure page says SAP 10.3 is currently the sole approved methodology and that HEM will be introduced alongside it. The HEM consultation outcome describes a limited period of dual running and says government will explore integrating HEM into EPCs. These statements do not provide a project-specific instruction to commission a HEM assessment today. Keep a record of the official position checked when appointing an assessor. Ask what can be delivered under the available route, and distinguish that work from preparation for a future change.
When Home Energy Model is needed
The Future Homes Standard is the latest version of Part L, covering energy performance. Approved Document L (2026) has been published. GOV.UK Building Circular 01/2026 says the amending regulations come into force on 24 March 2027, with later dates for higher-risk building work, subject to transitional provisions.(Source: Approved Document L: Energy and greenhouse gas emissions (2026) (GOV.UK); GOV.UK: The Future Homes and Buildings Standards, Building Circular 01/2026; GOV.UK: Energy calculation as a service (ECaaS), access the Home Energy Model)
GOV.UK's Standard Assessment Procedure page, updated in June 2026, says HEM did not launch at the same time as the Future Homes Standard, that SAP 10.3 is currently the sole approved methodology, and that HEM will be introduced alongside SAP 10.3 in the coming months. GOV.UK has not given a start date for HEM.(Source: GOV.UK: Standard Assessment Procedure; GOV.UK: Home Energy Model, replacement for the Standard Assessment Procedure (consultation outcome); GOV.UK: Home Energy Model, Future Homes Standard assessment (consultation outcome); Approved Document L: Energy and greenhouse gas emissions (2026) (GOV.UK); GOV.UK: The Future Homes and Buildings Standards, Building Circular 01/2026)
The consultation outcome on HEM as a replacement for SAP says both HEM and a version of SAP will be available for a limited period before HEM becomes the sole method. It also says government will explore integrating HEM into EPCs. The HEM engine is being developed on the Energy Calculation as a Service (ECaaS) platform.
We will not give a HEM start date until GOV.UK publishes one. If you read a date elsewhere, check it against the GOV.UK pages linked below.
Home Energy Model status at last review
How this tool decides
Otherwise / result rule
As reviewed on 14 November 2026, SAP 10.3 is the sole approved method and HEM has no announced start date.
This is the page’s dated status, not a live launch check. Part L commencement on 24 March 2027 is subject to transition; it is not a HEM launch date. The displayed range is borrowed from SAP calculations. GOV.UK: Standard Assessment Procedure; page reviewed 14 November 2026
Typical project: £95 to £330 per dwelling.
Indicative only. This is a typical UK market range based on prices published by other providers, checked November 2026. It is not a quote. Prices exclude VAT unless stated. Contact us for an accurate price for your project.
No published price was found for this service. The range shown is borrowed from SAP calculations.
Checked November 2026.
Next step: Confirm the current approved method and applicable edition before arranging your assessment.
Deadline: Confirm the edition before the design submission or start of work.
What to have ready
- Plans and sections identifying the proposed dwelling types and plot references.
- A dated fabric specification with the current glazing schedule.
- Heating, hot water, ventilation and renewable system proposals.
- The project programme and available Building Control correspondence about the applicable route.
- A list of assumptions or product choices still awaiting design-team agreement.
How we work this out
The figures shown are indicative. They are ranges taken from prices that UK providers of this service have published, and they are here to help you budget. They are not a quote, an offer or a price guarantee from National Building Compliance.
Your actual price depends on details this tool cannot see, including the size and layout of the building, how many units there are, access, location, how complete your drawings are, and how quickly you need the work. It may be lower or higher than the range shown.
Unless a figure says otherwise, prices exclude VAT. The date each range was last checked is shown beside it.
For an accurate, fixed price, send us your project details. We will confirm the scope and quote before any work is booked.
Indicative market costs
| Case | Unit | Indicative range |
|---|---|---|
| Typical project | per dwelling | £95 to £330 Indicative only. This is a typical UK market range based on prices published by other providers, checked November 2026. It is not a quote. Prices exclude VAT unless stated. Contact us for an accurate price for your project. |
No published price was found for this service. The range shown is borrowed from SAP calculations.
Checked November 2026.
Home Energy Model for typical project in England typically costs £95 to £330 per dwelling before VAT, based on prices published by UK providers and checked in November 2026. This is indicative and not a quote.
Indicative only. This is a typical UK market range based on prices published by other providers, checked November 2026. It is not a quote. Prices exclude VAT unless stated. Contact us for an accurate price for your project.
Comparing project inputs for Home Energy Model
| Project input | Practical check |
|---|---|
| Model preparation | Organise drawings and product evidence. |
| Method approval | Check the current official methodology position. |
| Project submission | Confirm the assessment route for the actual project. |
(Source: GOV.UK: Standard Assessment Procedure)
What affects the cost of Home Energy Model
Home Energy Model enquiry pricing needs a defined scope: preparation of project information is different from producing an approved compliance assessment. Dwelling variations, model detail and later specification changes affect the work involved. Confirm the available assessment route and deliverables before agreeing a fee or programming a submission.
Price: [[TO SUPPLY: Home Energy Model price from]]. Turnaround: [[TO SUPPLY: Home Energy Model turnaround time]].
How the Home Energy Model service works
You tell us about the new homes you are planning and when work will start.
We confirm which edition of Approved Document L applies, including any transitional provisions.
An accredited assessor prepares the compliance calculations in SAP 10.3, the approved method today.
When HEM becomes available for compliance, we confirm whether your project can or must use it.
You receive the design-stage and as-built reports Building Control needs.
We keep you informed of any GOV.UK announcement that affects projects already under way.
Which projects need Home Energy Model?
- Housebuilders planning later phases
- Keep each phase’s drawings and programme distinct. Ask for the applicable calculation route to be checked when commissioning the assessment rather than assuming a future method will be available.
- Self-builders choosing services
- Retain product performance data and record undecided choices. These records support a clear assessment brief without predicting a future HEM result.
- Architects updating specifications
- Separate confirmed project decisions from assumptions about future calculation tools. Record the official guidance relied on when the assessment scope is agreed.
Information to prepare for Home Energy Model
- Plans and sections identifying the proposed dwelling types and plot references.
- A dated fabric specification with the current glazing schedule.
- Heating, hot water, ventilation and renewable system proposals.
- The project programme and available Building Control correspondence about the applicable route.
- A list of assumptions or product choices still awaiting design-team agreement.
Questions about Home Energy Model
What is the Home Energy Model?
The government's new method for calculating the energy performance of homes. GOV.UK says it will replace SAP.
When does HEM start?
GOV.UK has not given a date. It says HEM will be introduced alongside SAP 10.3 in the coming months.
What should I use now?
SAP 10.3. GOV.UK says it is currently the sole approved methodology.
When does the Future Homes Standard apply?
Building Circular 01/2026 says the amending regulations come into force on 24 March 2027, subject to transitional provisions.
Will HEM affect EPCs?
GOV.UK says government will explore integrating HEM into EPCs. No change has been confirmed.
How much will a HEM assessment cost?
Prices will be set once HEM is available for compliance: [[TO SUPPLY: price from]]. Turnaround: [[TO SUPPLY: turnaround time]].
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