How to read an EPC

An EPC is a legal document, and once lodged on the Landmark Register is valid for 10 years (or until superseded).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. 

The next item is a 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.

Reference Number: A unique reference number is allocated at the time the EPC is lodged on the National Data Base.  

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

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.

The section above aims to show how much an ‘average household’ could expect to spend if they lived in a semi-detached property with a floor area of 128m2  taking into account the thermal properties of the roof, walls and floor as input by the DEA. The figures are always based on the same assumption. These figures do not take into account how the family living in the property uses the heating and lighting appliances which are present. They are based on figures pre-determined in the SAP methodology.

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.

Top Actions to make your home more efficient

This section seeks to point out the most effective measures which can be taken to improve the subject property.

Where a green tick is shown against an improvement this indicates it could be eligible for Green Deal finance because repayments are calculated as being no more than energy cost savings for that measure.

Where an orange tick is present that measure may qualify for inclusion, but additional finance will be necessary as repayments are likely to exceed energy savings costs.

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 (Star Rating)

The star ratings are based on u-values for most elements – the better the u-value the more stars are allocated, except for floors and secondary heating which are not allocated a rating.


The number of stars 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 star rating is allocated once the unit price is referenced from SAP Table 12 and divided by a factor for the water heating efficiency.

At the foot of the dwelling’s features is information about primary energy use. 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 Primary 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.

Opportunity to benefit from a Green Deal on this property

This section just advises that the property may be eligible to benefit from a Green Deal Plan to pay for measures which improve the energy efficiency of the dwelling.  The recommended improvements are listed on page 3.

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:

Alternative Measures

Measures which the householder may wish to also consider are listed separately. Detail is given at the foot of page 3 about where to find an online tool which illustrates how to save money on fuel bills, and for considering which measures to select for Green Deal finance.

The final page 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 DEA’s accreditation number is also shown in this section.  

Impact on the Environment

This 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.

Home Heat Demand

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

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




If you need help get in touch!

Fill out our short contact form below if you would like to find out more about the information displayed on this page


Related Links

Assessor Search

How to read an EPC?


Success Stories

"As usual Elizabeth's presentations are of extremely high quality, she explains concisely and also clearly. All questions are answered, and she has time to ensure that everyone understands the material."

- H. Stevens, Overcoming QA Issues


Find out more about the range of services Elmhurst Energy has to offer.

Tech Support
© Elmhurst Energy Systems Ltd 2016. All rights reserved.