Although the construction industry has seen many targets on building energy efficiency introduced through legislation such as Part L of the Building Regulations, or Minimum Energy Efficiency Standards, there is currently no agreed definition of a ‘net zero carbon’ building.
However, many leading organisations such as CIBSE, BRE, and Better Buildings Partnership (BBP). London Energy Transformation Initiative (LETI) and others are working on a Net Zero Carbon Standard for buildings. The work will bring together several reports and guidance documents to provide a single, agreed definition and approach to delivering net zero carbon.
The Net Zero Carbon Standard proposal defines a net zero carbon (whole life) built asset as:
“One where the sum total of all its asset related greenhouse gas emissions, both operational and embodied, over an asset’s life cycle are minimised, meet local carbon, energy and water targets and with residual ‘offsets’, equals zero.”
Net zero carbon and energy efficiency – an important link
While a net zero building and an energy efficient building are not necessarily the same, designers and building owners targeting net zero carbon emissions must also have energy efficiency as a key consideration.
CIBSE and LETI define net zero carbon – operational energy in a building as:
“A Net Zero Carbon – Operational Energy asset is one where no fossil fuels are used, all energy use has been minimised, meets the local energy use target (e.g. kWh/m2/a) and all energy use are generated on- or off-site using renewables that demonstrate additionality. Direct emissions from renewables and any upstream emissions are ‘offset’"
Since HVAC equipment in a commercial building can use up to 40% of its energy, it’s vital to focus on the specification of energy efficient systems and their long-term efficient operation.