Last edited 14 Aug 2017

Dwelling emission rate DER

The Building Regulations set out requirements for specific aspects of building design and construction. Regulation 26 of the building regulations states that “Where a building is erected, it shall not exceed the target CO2 emission rate for the building…”,

The target CO2 emission rate (TER) sets a minimum allowable standard for the energy performance of a building and is defined by the annual CO2 emissions of a notional building of the same size and shape to the proposed building. TER is expressed in annual kg of CO2 per m2.

The Dwelling emission rate (DER) is the actual CO2 emission rate of self-contained dwellings and individual flats (excluding common areas) based on their actual specification.

The DER for the proposed building must not exceed the TER.

Before construction begins, a design stage calculation must be issued to the Building Control Body (BCB), setting out the TER, and DER for the proposed building, along with details of its proposed specification.

Within 5 days of the completion of the construction, a report must be issued to the Building Control Body (BCB), setting out the TER, and DER of the completed building, along with any changes that have been made to the specification, and an energy performance certificate (EPC). These ‘as-built’ calculations require that an air-permeability test is carried out to ensure that the building envelope has been constructed to a suitably high level of workmanship so that air (and with it, heat) will not ‘leak’ through the building fabric. In addition, the BCB is likely to require a commissioning notice.

The TER and DER can be calculated by following the Standard Assessment Procedure (SAP). This can be done by using a computer program approved for SAP calculations by BRE on behalf of the government.

NB 2013 changes to part L of the building regulations which came into force on 6 April 2014 introduced a Target Fabric Energy Efficiency (TFEE) rate for dwellings to sit alongside the Target Emission Rate. The TFEE is the minimum energy performance requirement for a new dwelling. The Dwelling Fabric Energy Efficiency (DFEE) rate is the actual energy performance of the new dwelling. The DFEE must not exceed the TFEE. See Target fabric energy efficiency rate for more information.