DEC (display energy certificate)

DECs are legal obligations for public access buildings with a floor area over 250m². They need to be made publicly visible in the building itself (this would normally be an entrance foyer or reception area), also accessible and easy to find online.

DECs are important because they show the 'operational' energy performance of a building and are based on the actual energy consumption. The certificate and grade (A-G) is updated every year and comes with a full recommendation report, which indicates and prioritise the next steps in order to achieve a higher grade. Other useful information such as the building's carbon footprint and running costs can also be ascertained from a DEC. The DEC has to be renewed annually, but the recommendation report lasts for seven years.

DECs show the actual energy usage of a building, the 'operational rating', and help the public see the energy efficiency of it. This is based on the energy consumption of the building as recorded by gas, electricity and oil usage.

EPC (energy performance certificate)

EPCs are also graded A-G (much like the energy rating stickers on the back of white electrical goods). They assess the 'designed' energy performance and are a legal requirement for any new build or significant retrofit. The government has introduced minimum energy efficiency standards (MEES) for the private rented sector, setting out minimum standards for EPCs which are ramped up at set intervals. This will be a D rating (2023), uplifted to a B by 2030. Any assets that are to be sold or leased that fall below this rating may be classed as 'dead assets' which are unsellable or unlettable.

• MEES legislation in full 
• Further guidance
• Domestic private landlord MEES guidance
• Non-domestic private landlord MEES guidance

An energy performance certificate is required for properties when constructed, sold or let. It provides an assessment and indicator as to the energy performance of any given building (domestic or non-domestic) and what you can do to improve it. They're not quite as useful as DECs since they don't reflect the building's true operational performance, but they're still a useful guide nonetheless. EPCs apply to all buildings with few exemptions, but are generally only done when a building is sold or leased. EPCs again come with a recommendation report attached, which prioritises the next steps and even has some ball-park costs for retrofit works. EPCs calculate the financial and carbon savings based on building design criteria and modelling. With this method it estimates the designed running costs (but it's not a good indicator of actual operational performance).

You can find an energy certificate (DEC or EPC) by searching for a property by its postcode. We use qualified energy assessors to carry out both DEC and EPC assessments.