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.

BUILDING FABRIC

U-values and condensation risk.
Every layer accounted for.

Clear thermal and moisture-risk calculations for walls, roofs and floors, based on the actual proposed construction.

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U-value calculations for building elements

We calculate the thermal performance of proposed or existing walls, roofs and floors using the project-specific layer build-up. The output provides a clear U-value and records the materials, thicknesses, conductivities and assumptions used.

Condensation risk reviewed through the build-up

Where moisture behaviour needs to be assessed, we review the order of layers, vapour resistance, insulation position, cavities and membranes. The report highlights the calculated risk and any design points that require clarification or improvement.

Useful evidence for the wider project

The results can support SAP or SBEM inputs, Building Control queries, retained-element reviews, refurbishment decisions and coordination with the architect or contractor. Accurate construction information is essential, so assumptions are stated rather than hidden.

COMMON QUESTIONS

Clear answers.
No guesswork.

01What information should I provide?+

Send the full construction build-up from outside to inside, including each material, thickness, insulation product, membranes, cavities and framing where applicable.

02Can you assess an existing element?+

Yes, where enough evidence is available. Drawings, opening-up photographs, product information and survey notes can help establish a reasonable build-up, with any assumptions clearly recorded.

03Does a U-value calculation include condensation risk?+

Not automatically. They are related but distinct assessments, so tell us if the project specifically requires a condensation risk analysis.

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