The quality of Energy Performance Certificate assessors have been called into question by surveyor firm Re:volve Real Estate, which said the same properties are being assessed inconsistently.

The firm said it regularly sees “flawed” EPC assessments which are later revised.

There were therefore calls for better accreditations for assessors, with some apparently being qualified after a short two-week course.

Andy Heath, senior building surveyor at Re:volve Real Estate, said: “As building surveyors, much of our work and recommendations rely on the EPC ratings of our projects. However, we often encounter significant fluctuations in these ratings, depending on the assessor and when it is completed.

“We frequently have to reevaluate projects that were initially assessed by qualified professionals, as we find that the true rating actually falls within band B instead of its current D rating.

“A large proportion of issues are as a result of assessors not sourcing quality and confirmed data. Often ratings are finalised off assumptions and is a key downfall within the industry.”

Heath added: “I believe I can speak on behalf of my peers when I say that the accreditation required for assessing a building’s energy does not meet the industry’s standards.

“We work with professional EPC assessors who are up against assessors with minimal qualifications from a short two-week course.

“The ever-changing model means that energy ratings are in a constant state of flux, creating significant legal complications for our clients who are constantly trying to keep up with shifting standards.

“To challenge this head-on, improved accreditation standards are essential to bolster the credibility of assessments and minimise errors, biases, and discrepancies.”

Re:volve Real Estate said this was particularly evident at its recent Gordon House project, a 30,000 sq ft office space near Preston.

The firm said it discovered a significant difference between the required assessment and the one conducted. Despite the project’s complexity, warranting a Level 4 EPC Assessor due to its intricate HVAC system, the assessment was carried out by a Level 3 Energy Assessor.

As a result, the initial assessment yielded a much lower D EPC rating, which was below the expected standard for a building of this calibre and rendered the rating inaccurate. However, upon reassessment by a properly qualified Level 4 assessor, the EPC rating was upgraded to a B, reflecting the true energy efficiency of the building.

Heath said: “We routinely find assessors assuming aspects of the building such as its U values, air permeability rate, level of insulation, heating systems, windows and lighting.

“We take great care to rectify the flawed work left by subpar assessors. We prioritise retaining As Built information to ensure that future assessments are based on actual data rather than assumptions. This approach not only enhances the accuracy of assessments but also leads to improved EPC ratings.

“Qualifications for assessors would improve industry standards and enable assessors to work more efficiently and with better accuracy.

“Implementing higher standards universally will lead to enhanced industry performance, increased compliance, and a raised bar for excellence.”