Building Research Establishment: Errors in Green Guide ratings

Confusion surrounds the Building Research Establishment’s (BRE) Green Guide ratings after it blamed the industry for the late supply of data and “an error in one of the algorithms” for misleading results in its revised information spreadsheets.

According to one industry source, manufacturers are concerned BRE may have unwittingly misled developers that expect to achieve a particular level of the Code for Sustainable Homes by calculating incorrect ratings.

The BRE is not due to publish its final version of the Green Guide to Specification that will work with the Code for Sustainable Homes until later this year.

The source told CJ: “BRE has met with members of the Construction Products Association explaining what they’ve done with the Green Guide and the website. They said there had been a mistake and that some of the revised ratings were wrong. Some materials suppliers that appeared to perform well under the new ratings may be disappointed.”

In a statement, the BRE said that the Code specifications were published on the basis that they could be subject to change and blamed delays in receiving data from manufacturers.

“This situation arose out of the need to undertake further data consultation work with industry trade bodies and from severe delays suffered in industry supplying data to the Green Guide update project,” a spokesman said.

“The current situation should not lead to assessments that are misleading. Ratings calculated at the current time and based on the provisional Code Green Guide to Specification ratings will be honoured.”