How to read an EPC

An EPC is a legal document, and once lodged on the register is valid for 10 years (or until superseded). It is important that the address shown at the top of the first page is accurate. Please note this page details how to read an EPC for England, Wales, and NI; for information about reading an EPC on the Scottish register, click here.

The next item describes the opening of the EPC:

Date of validity: This shows when the exact date that the EPC will expire.

Certificate Number: The certificate number will be displayed underneath the energy rating at the top of the page.

Property Type: A description of the type of property, eg. end-terrace house, office, etc.

Total Floor Area: The internal floor area of the property is shown, based on the measurements taken by the assessor at the time of their visit.

Energy Efficiency Rating

The illustration below indicates the final ‘score’ – the energy efficiency rating for the property. The higher the figure in the ‘current’ column the more energy efficient the property. The figure in the’ potential’ column is based on the recommendations which appear later in the report.

The costs involved in calculating the final result are updated by the Building Research Establishment only when new versions of SAP are introduced. For example, during December 2014, use of SAP 2009 was discontinued and replaced by the full SAP 2012 document and the fuel prices were simultaneously updated.

It is possible, therefore, for an EPC created after introduction of a SAP upgrade to register a score which is worse than one previously lodged for the same house, with the same input. This is because an increase in the price of fuel has been incorporated in the later version of SAP.

Summary of Property Features

This section shows a summarised description of the property’s elements. Where more than one type of element is present at the property, both types will only appear if the lesser type is more than 10% of the area of the total element. At most three different types will be shown on the completed certificate.

Energy Efficiency 

Features are now ranked on a scale of very poor (least efficient) to very good (most efficient), following on from the previous 'star rating' system.

The ratings are based on u-values for most elements – the better the u-value, the higher the rating - except for secondary heating which is not allocated a rating. 


The rating for lighting is based on a sliding scale of percentages of low energy fixed outlets present in the property.


Heating is rated according to the cost of a unit of heat supplied to the space. This means the unit cost of the fuel (expressed in pence/kWh) divided by the efficiency (expressed as a fraction) of the appliance. The unit costs are shown in SAP Table 12. Where a high and low rate applies, the unit is a weighting of the high and low rate prices according to the assumed number of kWh per year used at each price.


Domestic hot water is handled similarly to space heating; the rating is allocated once the unit price is referenced from SAP Table 12 and divided by a factor for the water heating efficiency.

SAP Table 12

At the foot of the dwelling’s features is information about primary energy use (shown below). Primary Energy use includes a factor which is the amount of energy used to produce one kilowatt of power for the household. The Primary Energy varies according to the fuel used in the dwelling for heating, hot water, pumps and lighting. Table 12 within the SAP 2012 document deals with fuel prices for the SAP rating but also includes the  Energy Factor per fuel which is multiplied by the amount of kilowatt hours the household uses to produce the figure for the EPC. It has no effect on the costs mentioned in the Estimated Energy Costs on the EPC. The actual SAP rating is based on that household’s assumed consumption.Primary Energy Use

Impact on the Environment

This next section is designed to provide information about the environmental impact of the subject property. The figures illustrate that by adopting the improvement measures shown under the Recommendations section on page 3, this could be reduced substantially.

Recommended Measures

Based on the information which has been input about each individual dwelling, the software will calculate suggestions for improving the energy efficiency, and these are listed in the format as shown below:

Property Energy Performance

Estimated energy use and potential savings

The estimated cost is not based on how energy is used by people living at the property. Instead it shows how much the average household would spend in this property for heating, lighting, and hot water.

Estimated Energy Use

Home Heat Demand

The figures which appear in this section are used when applying under the schemes such as the Renewable Heat Incentive (RHI).  

Details of the Assessor and Accreditation Scheme 

This part of the EPC gives full contact details of the Energy Assessor who carried out the assessment. Any queries about the content of the EPC should in the first instance be directed to the DEA. The DEAs accreditation scheme details are also shown in this section.  

It also shows the details about the description of the dwelling type: 

Date of Assessment: This must always correspond with the date on which the surveyor visited.

Date of Certificate: The certificate date is generated automatically on the day on which the EPC is lodged.

Type of Assessment: This section indicates whether the certificate was created using full SAP or reduced SAP methodology.

Assessor details


The last item on the EPC is the Addendum/Additional information section. This lists any additional information which the input relating to the property has generated. Using the example of a swimming pool, the following additional detail has printed.


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