What is an EPC?

An Energy Performance Certificate, otherwise known as an EPC, provides an energy rating for a home. The way in which EPC legislation is applied differed between England and Wales, and Scotland. Since October 2008, all properties in England and Wales require an EPC. In Scotland, residential properties marketed from 1st December 2008 have an EPC provided as part of the Home Report.

The EPC provides a rating of the properties energy efficiency and displays this as a graph, similar to those found on kitchen appliances. It doesn’t look at the appliances, but rather the performance of the building itself in areas such as heating and lighting. Ratings come on a scale of A-G, with A being the best rating. Most homes in the UK have a band D-E rating for both the Energy Efficiency and Environmental Impact.

The EPC also outlines some ideas which help to improve the building’s energy performance. Implementing these can lead to lower energy bills, reduced carbon deposits and can make homes more attractive to potential buyers.

Energy Rating of Properties

Homes are energy rated into one of seven bands from A to G, where A is high efficiency and G is low efficiency. This is a similar system to the energy rating of domestic electrical goods and new motor vehicles. An energy rating is calculated by entering data from a survey (property dimensions, wall construction, boiler type, loft insulation etc.) into a computer program which generates an output rating on a scale from 1 to 100 (1 being a low rating and 100 being a high rating). This energy rating is linked to the cost of heating, lighting and hot water per square metre of the property. The current average rating for a property in England and Wales falls within bands D - E. New build homes built to current building standards are likely to achieve a high C or low B rating.

Estimated heating costs

As well as producing an energy rating for the property, the EPC will give predicted annual heating, lighting and hot water costs. These are based on a standardised occupancy (according to floor area) and a standardised heating pattern. This assumes the heating will come on from 7 am to 9 am in the morning and 5 pm to 11 pm in the evening (Monday to Friday). At the weekend it is assumed the property is heated for 16 hours per day. The default temperatures are 21 OC for the main living room and 18 OC for the rest of the dwelling. This enables heating costs to be compared on a like-for-like basis and not on the actual use of the heating system by a homeowner. For example, there may be two identical dwellings, one of which is occupied by a single person who heats only one room for a few hours of the day, and the other is home to a large family heating the whole house for most of the day. Both will obtain the same scores on the A to G scale. The heating costs displayed are very sensitive to the type of fuel used by the heating system. Some fuels are much more expensive than others and are likely to result in a lower energy rating for the property.