The NHER (National Home Energy Rating) is a method of assessing the energy performance and fuel cost of a dwelling. It uses a similar data set to SAP but includes more detail on occupancy, location and appliance use to give a more accurate calculation of CO2 emissions and running costs for a specific dwelling. The NHER rating is not a statutory requirement. It is often used by affordable housing providers to give a good indication of potential running costs of new properties.

SAP stands for Standard Assessment Procedure, also known as Energy Ratings. Houses are rated from 0 - 100, 0 being very inefficient and 100 being highly efficient.

SAP ratings are the Government's standard methodology for home energy rating. SAP uses SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK) figures to calculate the energy needed for heating and hot water systems. SAP ratings are used by local authorities and housing improvement programmes to assess the energy efficiency of both new and old housing.