About Energy Ratings

Energy ratings tell you how energy efficient a home is. New homes already have energy rating applied to them, but in the next few years - due to UK and EU legislation - they will apply to all existing homes.

There are two main energy ratings available within the United Kingdom - the SAP rating and the NHER rating.

What is a SAP rating? The Standard Assessment Procedure (SAP) is the Government's recommended system for the home energy rating. The SAP energy cost rating is based on energy costs for space and water heating only.

A SAP rating is required for all new build dwellings and those which are undergoing significant material alteration (such as the addition of an extension to the dwelling). Housing Associations and Councils which own stock are all required to submit average SAP figures for their regions so that Government can monitor the amount of energy used, and associated carbon emissions, from dwellings in the UK.

The current version of SAP is SAP 2005 (v9.80). It has a scale of 1 to 100; 1 being very poor, 100 being excellent. A typical SAP for an average house in England is about 45. A SAP 2005 rating on a house built to current Part L building regulations would be closer to 80 or more SAP points.

How SAP Ratings Compate to the A-G Scale

SAP 2005 was introduced in England and Wales in April 2006. SAP 2005 will be the basis for the implementation of the Energy Performance in Buildings Directive. SAP 2005 is different to the previous version, SAP 2001, in that it takes account of building integrated renewable energy systems, and fixed internal lighting.

What is an NHER rating? The NHER rating takes into account the local environment and the effect it has on the building's energy rating. The NHER calculates the costs of space and water heating, but adds cooking, lights and appliances to give a comprehensive picture of energy usage in the home. This is why the NHER is more accurate than the SAP.

The NHER first emerged in 1983 at the Energy World Exhibition in Milton Keynes, and later the Government used a simplified version of this model which could be calculated by hand. This became known as SAP.
The NHER was conceived as a rating with as scale of 0.0 to 10.0. (0.0 being poor and 10.0 being excellent)

 An average dwelling in England would currently score between 4.5 and 5.5. A building meeting current Part L1 Building Regulations would probably score higher, perhaps around 8.0 or more.
The NHER scale was recently extended, with 20 representing zero total fuel costs.