Residential Properties... 

Information that affects the the energy efficiency of the property is gathered and recorded, this forms the basis of producing the Energy Performance Certificate. The property age, type and construction details will be noted and the overall perimeter and internal room height measurements will be taken. Inspection to record details of the main heating system, water heating and their controls will be taken. Access to mains service meters will also be needed. The type and level of any thermal insulation to the property will be noted, so access to any loft spaces will be needed. The type of glazing, fixed lighting and presence of any extensions or a conservatory will be also be noted.  

This data is then entered into a special computer program called the Reduced data Standard Assessment procedure (RdSAP) that calculates the energy efficiency and carbon emissions of an existing property based on the properties characteristics and main fuel type. The result is shown on easy to read scales, referred to as the Asset Rating exampled below. 

The Asset Rating is similar to those on appliances such as fridges & freezers   

The purpose of the EPC produced is to provide the home owner and potential buyer with information regarding the energy efficiency and environmental impact of the property. The property is rated in terms of energy use per square metre of floor area and the energy efficiency on fuel costs, with the environmental impact based on carbon dioxide (CO2) emissions. Two rating scales are produced for the property.

The Energy Rating  

This is a measure of the overall energy rating of the property. A rating is assigned between 0 (G) and 100 (A). The higher the rating the more energy efficient the property will be and therefore the lower the annual fuel costs are likely to be. 

The environmental Rating

This is a measure of the impact on the environment in terms of its carbon (CO2) emissions. This also is assigned a rating between 0 (G) and 100 (A). In this case the higher the rating the less impact the property has on the environment. 

The average property in the UK falls within bands D-E of both the ratings.

Improvement Measures

The energy report also includes cost effective improvement measures that can be taken to reduce the properties energy costs. These recommended measures are a guide only and the potential cost savings for the property with these measures taken is given. A potential overall energy efficiency and environmental impact improvement rating is also given if the recommended measures are taken as a comparison.

New Build Properties...     

New build properties still under construction and being marketed for sale require a Predictive Energy Assessment (PEA). This gives the property a predicted energy efficiency rating and also an environmental impact carbon emissions rating based on SAP calculations initially made at the buildings design stage. This document is required to be included in a Home Information Pack (HIP) when marketing new homes for sale. 

When the property is finally completed but if it remains unsold then the PEA has to be replaced in the HIP with an updated on construction EPC (ONEPC). The OCEPC is similar to the EPC issued on existing residential properties, and is also required for Local Building Control compliance purposes. 

An OCEPC is produced from a properties original building plan and design specifications and no site visit is usually required.  

To view a full example of a Residential Energy Performance Certificate, click on this link

To view an example of a Predictive Energy Assessment document, click on this link

To view information on Environmental Impact issues and Energy Saving ideas, click on this link 

To view a full example of a Commercial Energy Performance Certificate, click on this link  

Commercial Properties...

A commercial Energy Performance Certificate is required when a building is offered for sale or to let, and it should be available for when written information about a building is requested by a prospective buyer or tenant, or when a building is viewed by a buyer or tenant. In any event, an EPC must be obtained before a contract for sale or to let is entered into by the parties. 

Commercial properties are categorised for EPC assessment by qualified assessor's according to the buildings level of complexity served by their fixed service systems of heating, cooling and mechanical ventilation.

The types of commercial buildings that require having an EPC range from newly constructed to existing retail units, offices and industrial buildings to very large scale buildings such as out of town shopping malls and airports. Existing commercial buildings naturally ventilated with heating systems around 100kw output and with localised comfort cooling at around 12kw are the most common category and account for around 70% of the commercial building types in the UK. 

A commercial EPC is required by law on the construction, sale or lease of a building.

For the purpose of clarity of the regulations a building is defined as:

" a roofed construction having walls for which energy is used to condition the indoor climate and a reference to a building includes a reference to any part of a building which has been designed to be used separately". 

A commercial EPC assessment is quite different to that of a residential property.

A commercial EPC assessment differs to a residential one by the wider scope of information required to be collected about the building, and the time required for the data to be inputed into the SBEM software that produces the EPC and accompanying recommendations report for the building.

On a residential assessment only the external perimiter walls and construction type are noted and measured, with also the floor and roof types also recorded. During a commercial assessment however all building elements of external and internal wall constructions, floors, ceilings and roofs are recorded and their areas measured, external windows and access doors are also recorderd and measured.

The overall building is then internally divided into separate zones for data collection and calculation purposes, these zones are determined by the activity within them and by the level of natural daylight entering them and also the type of fixed heating, cooling, ventilation and electrical lighting serving the zones. 

With many existing buildings there may not be any current building plans or a log book with details of any history of fixed services and the lighting types within the building. In these cases a full detailed building inspection will need to be carried out and also floor plan drawings of the building completed.  

The computer software program used to calculate the energy efficiency and carbon emission rating of a building is called the Simplified Building Energy Model (SBEM). This calculation methodology is also used for checking for Building Regulation Part L compliance purposes. 

The Energy Performance Certificate records how energy efficient a building is and provides this on a A to G rating scale. The energy performance of a building is shown as a carbon dioxide (CO2) based index rating. These ratings are produced using standards, methods and assumptions about energy use so that the energy of one building can be compared with another building of the same type. 

Two other comparision ratings are also given which shows a rating if the building was newly built to current regulations and also that of a similar building of the same type.

The EPC is always accompanied by a recommendations report that details cost effective and other improvement measures to help reduce energy costs and carbon emissions of a building. 

A commercial EPC when lodged on the National Register is valid for 10 years or until replaced by a newer one.

Local IDEA

A Good IDEA For Local Independent Energy Assessment