What are SAP calculations and when are they required?

SAP calculations assess the predicted energy performance of a dwelling. They are commonly required for new-build homes, conversions and certain extensions to demonstrate Part L compliance.

What is needed for an on-construction EPC?

The final SAP or SBEM model must reflect the completed building, supported by confirmed construction specifications, test results and commissioning evidence.

What does an Energy Statement include?

An Energy Statement normally describes planning policy, the proposed energy strategy, demand-reduction measures, low-carbon systems, renewable energy and the resulting carbon improvement.

NEW HOMES & DEVELOPMENTS

New-build SAP calculations
from design to handover.

Design-stage modelling, practical specification advice and final EPC support for new houses, apartments and residential developments.

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Start while choices are still flexible

Early SAP modelling tests fabric, thermal bridging, heating, ventilation, air permeability and renewables before procurement. This gives the design team time to select a coordinated, buildable specification.

Optimise the route to compliance

If a design falls short, we identify which changes produce the greatest benefit and compare their effect. Advice is focused on practical decisions such as glazing, airtightness, heating flow temperature, ventilation and solar PV.

Close out the as-built assessment

At completion we update the model to the installed specification, review photographs and commissioning information, incorporate the air-test result and prepare the final compliance reports and EPC.

RELEVANT PROJECT EXPERIENCE

Similar buildings.
Practical outcomes.

Selected anonymised examples showing how the assessment supported design, compliance or completion.

Low-energy new dwelling

Fabric-first home with ASHP, MVHR and solar PV

The dwelling was assessed using high-performance fabric, triple glazing, mechanical ventilation with heat recovery, an air-source heat pump and rooftop PV.

The final design achieved an A-rated result with emissions below zero in the SAP model.

Residential development

Repeated house types coordinated efficiently

Shared construction, heating and ventilation assumptions were established once, with individual geometry and orientation reflected for each dwelling.

A consistent compliance approach reduced repeated queries across the design team.

COMMON QUESTIONS

Clear answers.
No guesswork.

01When should SAP calculations start?+

Ideally before the building fabric and services are fixed. Early assessment leaves more practical and cost-effective options available.

02What is needed for the first assessment?+

Scaled plans, elevations, sections and the proposed fabric, glazing, heating, hot-water, ventilation and renewable specifications.

03Is the design-stage SAP the final EPC?+

No. The model must be updated to reflect the completed building and supported by as-built evidence before the final EPC is lodged.

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