A Standard Assessment Procedure (SAP) calculation gives a home an energy rating of 1 to 100+. The rating is dependent on a number of factors, for example:

  • the built structure of the home;
  • its heating and hot water system;
  • internal lighting;
  • any renewable technologies used in the home.

The higher the rating the lower the fuel running costs, with 100 representing zero energy cost. Dwellings with a rating in excess of 100 are net exporters of energy.

SAP calculations result in a Predicted Energy Assessment or, when the building is complete, a New Build Energy Performance Certificate. These documents allow potential purchaser to compare the energy running costs of dwellings anywhere in the United Kingdom. This is achieved because the calculations are independent of location and are based upon a notional standard occupancy that overcomes variations associated with physical location and the differing ways in which people utilise their homes.

The client submits drawings, plans and specifications of the development to the assessor.

SAP Calculations are completed in four stages:

1) Design - Draft stage

From the plans and drawings the assessor prepares summary numerical information of the building, which includes: the total floor area of the dwelling; the floor area of the lounge or living room; the areas of the heat loss floors, heat loss walls and heat loss roofs; dimensions of any external windows and doors; the heights of each floor.

From the specifications provided the assessor calculates the thermal performance of the building’s elements such as heat loss floors and heat loss walls. These are expressed as 'U' values. ‘U’ values measure the rate at which heat passes through the fabric of the building, therefore, the higher the 'U' value the greater the rate of heat loss.

2) The assessor uses a computer software program to input data for the SAP calculation. The data entered relates to:

  • The type of dwelling
  • Floors
  • Walls
  • Roofs
  • Openings (windows, doors, rooflights)
  • Ventilation
  • Main and secondary space heating
  • Hot water generation
  • Use of renewable technologies such as phovoltaics and solar water heating
  • Lighting

3) The computer program determines whether the proposed dwelling will pass the Building Regulations with regards to the Conservation of Fuel and Power. The assessor is able to use the software to model different variations of the dwelling’s design.

The assessor reports back to the client.

4) The client validates the information provided by the assessor.

5) Design - Final stage

The client and the assessor agree a finalised version of the design, sometimes following several amendments to the initial design.

6) The assessor provides reports that the client may need to submit to the appropriate building control officer. For new dwellings this will include a Predicted Energy Assessment (PEA). The Predicted Energy Assessment will be included in the property’s Home Information Pack while the property is marketed off-plan.
7) As Built - Draft stage

The client continues with the build until completion.

8) For new dwellings an air pressure test will normally be required, and the client arranges for this to be undertaken by a suitably qualified operative.

The client reports back the results of the air pressure test to the assessor and also advises the assessor of any variations from the previously agreed Design - Final specification.

The assessor edits the SAP calculation to reflect the results of the air pressure test and any variations to the Design - Final specification. The software is used to check that the completed dwelling still meets the requirements of the building regulations with regards to the Conservation of Fuel and Power. If it does not the assessor recommends remedial action.

9) The client validates the information provided by the assessor.

10) For new build dwellings the assessor checks to ensure that the dwelling is registered on the government's central database register of national property addresses. If it is not the assessor arranges for the address record to be created.

11) As Built - Final stage

The assessor finalises the SAP calculation and creates the On Construction Energy Performance Certificate (OCEPC). The OCEPC must, by law, be displayed in a new dwelling, and be included in the property’s Home Information Pack.

Non-domestic Energy Performance Certificates-

Don’t risk a fine- The maximum penalty for non-compliance is currently £5,000, enforceable by Trading Standards. The penalty notice also includes the requirement to produce a valid EPC.
  • © 2009–2012 EnCert Limited. All rights reserved.
  • Terms & Conditions
designed & maintained by Pepperneck