The communities department has revised its rules on energy certificates to allow one certificate to cover a whole estate if data cannot be collected for individual buildings before the October deadline.

The concession, which applies to display energy certificates (DECs) and will last for a year, will give organisations with several buildings on one site time to fit energy meters to them.

Brian Scannell, the managing director of energy assessment company NES, said it was annoying that the change had been made so close to the deadline as it made it difficult to plan ahead.

He said: “This should have been entirely predictable from a long time ago.” However Scannell added that it was evidence that certificates were having a positive effect on energy use because it was making energy managers fit meters.

DECs show energy use and are required for buildings larger than 1,000m2 that are used by the public.