Prepared for Building Control approval

SAP Calculations (Standard Assessment Procedure) are the UK government’s mandatory, approved method for assessing and confirming the energy performance and environmental impact of new residential buildings, conversions, and certain extensions. The calculations are a desk-based exercise, performed by an accredited SAP assessor using architectural plans and building specifications. 

Purpose for Building Control Approval

The primary purpose of SAP calculations for Building Control approval is to demonstrate that the proposed dwelling complies with Part L (Conservation of Fuel and Power) of the UK Building Regulations. Without a “pass” on the SAP assessment, a building control officer cannot issue final sign-off, meaning the property cannot be legally sold or rented. 

The SAP assessment is carried out in two stages: 

Design Stage: Performed before construction begins to confirm the plans are compliant, producing a Predicted Energy Assessment (PEA) and a design-stage compliance report.

As-Built Stage: Completed after construction, incorporating final details and an airtightness test result to produce the final SAP report and the legally required Energy Performance Certificate (EPC). 

Key Metrics and Information

The SAP calculation uses approved software to model the building’s energy balance and compares the actual design against a notional (benchmark) dwelling of the same size and shape. It evaluates several key metrics: 

Dwelling Emission Rate (DER) vs. Target Emission Rate (TER): The actual predicted CO₂ emissions must be no greater than the maximum permitted emissions.

Dwelling Fabric Energy Efficiency (DFEE) vs. Target Fabric Energy Efficiency (TFEE): The energy demand required to heat the home must meet or exceed the minimum fabric performance standards.

SAP Rating: A score from 1 to over 100+ that indicates the dwelling’s energy-related running costs and overall energy efficiency (higher is better). 

The calculations take into account a wide range of factors:

Building Fabric: Materials used in construction, thermal insulation (U-values) for walls, floors, roofs, and windows.

Heating and Hot Water Systems: Efficiency and type of systems, including controls and fuel source.

Ventilation and Air Leakage: Performance of ventilation equipment and the building’s airtightness.

Internal Lighting: Percentage of low-energy lighting.

Renewable Technologies: Any incorporated solar panels, heat pumps, etc..