Energy Performance Certificates at Clovelly

Jonathan Taylor


  Traditional terraced houses on the steep main street of Clovelly  
  The main street of Clovelly, Devon (Photo: Jonathan Taylor)  

Energy Performance Certificates (EPCs) are needed whenever a property is built, sold or rented. The EPC indicates the energy efficiency of the property as estimated by the standard assessment procedure (SAP). The higher the score the lower the running costs are likely to be, with 100 representing zero energy cost. EPC band A (most efficient) corresponds to a SAP score of 92-100, while band G (least efficient) corresponds to a score of less than 20 (see 'Sustainability Standards and Regulations' by John Edwards).

Listed buildings are generally exempt from the requirement, but often owners choose to have their properties assessed in any case. In Clovelly, a picturesque village on the North Devon coast, most of the buildings are rented to people who live and work in the region. John Rous, who owns and manages the estate, considers the EPC rating as a necessity in a competitive market for attracting tenants, whether or not the building is listed. With the help of Mukti Mitchell of the CosyHome Company, the estate has an ongoing retrofit programme to improve the EPC rating of their housing stock to at least band E, which is the minimum level set by the government for letting residential properties from April 2018. Measures are chosen to give the greatest economic return, taking into account not only improvements in EPC rating and fuel efficiency, but also any risk of damage to the fabric in the long term from the alterations.

Number of houses affected


Average per house

Cost per SAP point

Cost of work

SAP point gains

Night storage radiators





Room in roof insulation





Loft top-up insulation





Secondary glazing





Draught-proofing windows and doors





Data reproduced by kind permission of Clovelly Estate


There is growing recognition that some measures encouraged by the SAP system are inappropriate for traditional fabric, and the estate’s consultant was particularly concerned by the risks posed by solid wall insulation. Key areas for improvements therefore include roof insulation, draught exclusion, secondary glazing and high-specification night storage heaters which store more heat and control its release more effectively. EPC point gains are carefully simulated by an experienced EPC assessor and used as a guide for the work to each property. The table opposite summarises the likely benefits from each measure.

Loft spaces which were readily accessible already contain some insulation, but many of the houses have rooms within the roof space with sloping ceilings and dormer windows. These are more difficult to improve, requiring insulation between and below rafters and studs, before relining and re-plastering.

In terms of keeping the heat in, roof insulation and the draught-proofing of windows have the greatest impact, and for the attic bedrooms with uninsulated dormers, the cost per SAP is very good, despite its high cost. However, for gaining the most SAP points, the most cost-effective measure is the introduction of night storage heaters to replace a variety of older heating appliances. Although electricity generation and distribution has a relatively high carbon footprint, the SAP system encourages the use of modern night storage heaters because they use energy from the grid when demand is least.


The Building Conservation Directory, 2017


JONATHAN TAYLOR is the editor of The Building Conservation Directory and a co-founder of Cathedral Communications Limited. He studied architectural conservation at Heriot-Watt University, Edinburgh and has a background in architectural design, conservation and urban regeneration.

This case study was prepared with the help of Mukti Mitchell, CosyHome Company and John Rous, Clovelly Estate Company Ltd.

Further information


Conservation principles




Energy use

Environmental control

Heating engineers


Secondary glazing


Sustainable building materials

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