L1A: SAP calculations for new dwellings


L1A – SAP calculations for new dwellings

In order to demonstrate compliance with Approved Document L1A you must provide your Building Control Officer with a SAP calculation for each new-dwelling.

A SAP calculation is the Government’s approved methodology for calculating the energy performance of dwellings. All new dwellings must achieve a dwelling CO2 emission rate (DER) no greater than a target CO2 emission rate (TER). The SAP calculation process is in two stages:

  1. Design-stage

  2. As-built stage

Our experienced SAP assessors can guide you smoothly through compliance, from concept to completion. Our service includes all the support required to ensure every dwelling achieves a pass.


How Energytest can help

Fast and accurate SAP calculations at a competitive price.

Comprehensive advice and support to ensure you arrive at the most economic and feasible solution to achieve compliance.

One fully-inclusive fee covering:

  • All the consultancy required to ensure every dwelling achieves a pass.
  • Design-stage and as-built SAP calculations.
  • U-value calculations.
  • Energy Performance Certificates.

Single-source-solution for Building Regulation compliance. As well as your SAP calculations and EPCs we can provide:

Where Planning conditions have been applied, we can also provide Energy Statements and Code for Sustainable Homes / Home Quality Mark assessments as required.

Design-stage SAP calculations, showing a pass, must be provided to Building Control before you start on site.

We shall assess the dwellings based on the design-specification provided. If a pass is not achieved we shall put forward cost effective options to achieve a pass. For example, improvements to the heating system, increase in insulation, better performance glazing, or a more air-tight construction (see air leakage testing).

Once a satisfactory specification has been agreed we shall issue design-stage SAP reports for submission to Building Control.

As-built SAP calculations must be provided to Building Control as part of their final sign-off procedure.

Upon completion of the construction works we shall update the design-stage SAP calculations to incorporate any changes to the design, manufacturer details for all heating systems and the as-recorded air permeability rate.

We shall then issue as-built SAP reports and an Energy Performance Certificate.

For developments in Scotland, in order to comply with Section 6 of the Building Standards SAP calculations will be required for each new dwelling. As with Approved Document L1A, design-stage SAP calculations are required before works start on site and as-built SAP calculations along with an Energy Performance Certificate are required post construction.

  • Floor plans, elevation drawings, section drawings and a site plan;

  • Construction specification;

  • Mechanical and electrical specification; and

  • Details of any renewable technology, such as solar hot water or photovoltaics.

What our clients say:

“I have used Energytest for all our SAP calculations since being introduced to them over two years ago. They are a very professional team and I always know that I am in safe hands not only to get the SAP calculations done efficiently and on time, but most importantly I rely on their experience and knowledge to specify the right elements for the building fabric.

Energytest are an important part of the design process and their input is greatly appreciated on all our projects where they are involved producing SAP calculations, EPCs and Energy Assessments.”

N Peshkepija MCIAT – Churchill Hui

Approved Document L1A