Which? mystery shopped EPCs and claim that they are in need of reform and should be enhanced.

The consumer champion selected 12 Which? members who were homeowners across England, Wales and Scotland and booked EPC assessments on their behalf during February to March 2024 to find out how accurate EPCs are. Their properties were built between 1650 and 1999 and ranged from a one-bedroom flat to a five-bedroom detached house.

Which? uncovered issues with the accuracy of the results and the recommendations that homeowners received.

One homeowner had their EPC survey done, but never received their certificate. The survey fee was refunded, but the homeowner was left in the dark about their home’s energy efficiency. Of the remaining 11 participants, just one was ‘very satisfied’ with their EPC and only three said they were likely to recommend getting an EPC, based on this experience.

Most participants (eight out of 11) told Which? their EPC did not appear to be accurate – they said the descriptions of key aspects of their home like the windows, roofs and heating systems were incorrect. That is not something that we have experienced here at Key One Property, and we understand that the assessors that we engage for our clients use a prescribed method to calculate scroring. 

Several participants in the mystery shop also felt that the recommendations suggested were unaffordable. One consumer said that they felt draught proofing was overlooked in their EPC report despite their home having an open chimney and front door with single glazing.

Peter and Carol Vermeulen in Aberdeenshire achieved a D rating for energy efficiency for their 1980s four-bedroom semi-detached bungalow in Aberdeenshire following their EPC assessment.

On receipt of the EPC, however, they noticed several discrepancies. There was no mention of their solar PV or solar thermal panels, or of a wood-burning stove. The suspended floor was described as uninsulated, although they had discussed their underfloor insulation with the assessor during the survey and offered to open an inspection hatch so this could be checked.

Which? contacted the assessor to point out the mistakes. After checking his survey notes, he admitted that there were omissions (which he blamed on the software) and offered to supply a new EPC.

The assessor issued a new, corrected EPC, with an improved B rating for energy efficiency. A better EPC can make a big difference for owners, as it allows them to command a higher price if they choose to sell and may make the home more attractive to tenants.

Megan Dobney also achieved a D rating for energy efficiency for her two-bedroom Victorian terraced house in London.

The EPC recommended several improvements, including internal or external wall insulation (typically costing £4,000 to £14,000 and saving £172 a year), suspended floor insulation (typically costing £800 to £1,200 and saving £70 a year,) solar water heating (typically costing £4,000 to £6,000 and saving £57 annually) and solar panels (typically costing £3,500 to £5,500 and saving £621 a year).

Installing all four could cost Megan up to £26,700 and she would only see the property rise by one band from D to C. She could save around £920 a year through installing all these energy efficiency measures – meaning it could take up to 29 years to recover the cost.

Megan said: “The recommended changes are extremely expensive, generally for small savings each year, and would require massive disruption.”

With millions of families across the UK worried about high energy bills, EPCs could provide valuable information on how people can save money and improve their home’s efficiency. However, they are in desperate need of reform.

Which? is calling for the next government to reform EPCs to make them a more reliable and useful tool for householders. In addition to addressing concerns about the accuracy and reliability of EPCs, Which? believes the design and content of EPCs should be reformed to ensure it provides consumers with the information and advice they need. This should include information to help consumers prepare for the transition to low-carbon heating.

EPCs should also be made more interactive, so that consumers can input information so that the advice is more relevant to their circumstances. EPCs should also include up-to-date costings relevant to the type of property and provide links to any financial support and a database of installers belonging to government-certified schemes.

EPCs are based on assessments by Domestic Energy Assessors, who can qualify through several different accreditation schemes that provide online and in person training. The next government should review auditing of EPCs and the training requirements for this role to ensure that assessors have the skills needed to complete reliable assessments.

Rocio Concha, Which? director of policy and advocacy, said: “With millions of families worried about high energy bills and the UK facing a big challenge to transition to low carbon heating, Energy Performance Certificates could be a helpful tool for consumers looking to save money and improve their home’s efficiency in the future.

“However, our research shows they are in desperate need of reform – with current certificates often inaccurate and only suggesting costly improvements with long pay back periods.

“The next government must make Energy Performance Certificates a more reliable and useful tool for householders. This should include reviewing the auditing and training requirements for Domestic Energy Assessors and ensuring EPCs provide relevant information and clear, actionable advice for consumers.”

Timothy Douglas, head of policy and campaigns at Propertymark, believes that EPCs could be better utilised through the introduction of a Property Passport to increase the uptake of energy efficiency improvements.

He explained: “This would enable information to be transferable across building owners and help maintain a long-term decarbonisation goal for the building.

“The process would not replace EPCs, but enhance them, creating an opportunity to capture EPC data digitally and add to it with other data over time. A Property Passport would also provide detailed guidance on the actions required, and already undertaken, to improve the property, based on building fabric and operational data helping building owners and occupiers make decisions to improve the energy efficiency of buildings.”