Last edited 09 Aug 2016

Energy targets for buildings

According to the Technology Strategy Board, in the UK, the built environment accounts for 45% of total carbon emissions (27% from domestic buildings and 18% from non-domestic), and 73% of domestic emissions arise from space heating and the provision of hot water.

Minimum standards for the conservation of fuel and power are set out in Part L of the Building Regulations. Part L sets standards intended to:

  • Limit heat losses and gains.
  • Provide efficient, effectively controlled and properly commissioned building services.
  • Provide the building owner with information allowing them to operate the building efficiently.

In order to achieve this the regulations and associated approved documents set out the following criteria:

  • The designed carbon emission rate (Dwelling Emission Rate (DER) for self-contained dwellings and individual flats (excluding common areas) and Building Emission Rate (BER) for buildings other than dwellings) must not exceed the Target Emission Rate (TER) for a notional building of similar type, size and shape.
  • Fixed building services should achieve a reasonable standard of energy efficiency. This is intended to prevent inappropriate trade-offs between different elements of the building. Minimum limiting parameters are set for key components of the building fabric to ensure that this is the case.
  • Solar gains should be limited.
  • As-built performance should be consistent with the DER. This includes air-permeability testing and appropriate commissioning of building services systems.
  • Provision should be made for energy efficient operation by providing the building owner with information enabling them to operate the building in a way that uses no more fuel and power than is reasonable. This might be done by the preparation of a building log book.

These requirements are becoming more demanding. However, it should be noted that energy predictions are not accurate. For example, they tend not to properly factor in occupant behaviour (such as the use of a great deal of electronic equipment, and the tendency not to switch things off when predicted) and so often fall short of the energy consumption of buildings in reality. See performance gap for more information. It is hoped that the roll out of Display Energy Certificates and the introduction of benchmarking services such as CarbonBuzz should help make predictions more accurate.

Clients may wish to exceed statutory requirements, and set their own energy targets. Perhaps they have existing standards which they would like to apply to the new development, they may wish to create an exemplar development, or they may simply wish to reduce running costs. Such targets should be established during the early stages of the project by the designers and the client so that they can be properly incorporated into the design and included in tender documentation. Energy targets need to be considered throughout the design process, from fuel appraisal investigations right through to window to wall ratios, floor to floor heights, slab thicknesses and insulation.

There are also a number of standards and accreditations that can be used to set energy targets such as:

In addition to the requirements of the Building Regulations, the National Planning Policy Framework makes clear that there should be a presumption in favour of granting planning permission for sustainable developments, this might include low-energy or low-carbon developments.

Schemes such as the CRC Energy Efficiency Scheme and the Energy Related Products Regulations have also been introduced to help encourage energy efficiency, and government initiatives such as the Green Deal, Feed in Tariff, Renewable Heat Incentive and the Climate Change Levy have introduced financial incentives.

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