A national housing developer association has published a report warning that proposed energy efficiency standards for new residential construction could add up to £18,500 per property to build costs — a finding it says will have significant implications for affordability, and which it has now submitted as the basis for a formal request to delay implementation pending an independent impact review.
The association noted that an independent impact review had already been commissioned following its previous submission on the same standards, but described the earlier review as having reached “preliminary-stage conclusions” and said it would not be appropriate to act on findings that had not yet been tested by a further review.
The new report models the cost increase across three scenarios: full compliance at current build costs; partial compliance with approved exemptions; and a third scenario described as Pathway Adjusted, which assumes the standards are modified before they come into force. All three scenarios show increased costs per unit. The association said this demonstrated the breadth of the impact across different compliance models. It did not include a scenario in which the standards were met through improvements in build efficiency, saying this fell outside the study’s terms of reference.
The report’s headline figure — an estimated £47 increase in average monthly mortgage costs — is based on the full compliance scenario, calculated over a 25-year mortgage at current rates. The document includes a supplementary appendix noting that improved thermal performance would reduce household energy bills by between £900 and £1,400 per year, on average. The appendix is marked optional reading.
An environmental standards body responded in a brief statement welcoming the publication of the appendix.
The association said it was calling for a six-month delay pending the outcome of the impact review, after which it expected to request a further delay pending a review of the review’s methodology. A spokesperson said this represented a “responsible, staged approach to evidence gathering” and that the organisation fully supported the principle of energy efficiency in new homes, which it had also said in its previous submission, and the one before that.
The government said the consultation remained open. The association said it was still consulting internally on whether to respond.
