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Code for Sustainable Homes - TER and DER Explained

(TER) Target Emission Rate

The Target Emission Rate is a number derived from modeling of an "as designed" building using the The Government’s approved methodology for assessing the energy performance of new dwellings. The current version is SAP 2009 version 9.90, dated March 2010, rev October 2010. The procedure accounts for energy used in:

•  Space heating and cooling
•  Hot water provision
•  Fixed lighting.

The indicators of energy performance are energy consumption per unit floor area, energy cost rating (SAP rating), environmental impact rating based on CO2 emissions (EI rating) and dwelling CO2 emission rate (DER). They are used in the production of energy performance certificates (EPCs) and to demonstrate compliance with AD L1A and the Code for Sustainable Homes.

To contribute to reducing CO2 emissions as calculated by SAP, heat and power must be generated either on or in the home, on the development or through other local community arrangements (including district heat and power).

For a mid terrace flat we might see a generated TER of 25 KgCO2/m2/year, depending on the code level required you will then have to tinker with the building envelope until you have the required reduction.

(DER) Dwelling Emission Rate

The DER is the estimated CO2emissions per m2 per year (KgCO2/m2/year) for the dwelling as designed. It accounts for energy used in heating, fixed cooling, hot water and lighting. The table below shows the necessary reduction depending on the require code rating.

DER_code_for sustainable_homes


TER - A target cooked up from SAP.

DER - Modeled Emissions for your particular development, based on SAP methodology.

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