The Green Building Council denies it's trying to undermine research that questions whether its Homestar rating tool is promising more than its delivering.
The programme run by the Green Building Council rates homes on a scale of 6 to 10 - with a rating of 6 or more said to provide assurances the house will be a better quality - including warmer, drier, healthier and cost less to run than a typical code compliant, new build.
But a study by two Auckland University researchers found properties rated 6 on the Homestar scale under-performed compared to other new builds - dropping below recommend minimum winter temperatures more than 55 percent of the time and quote chronically overheating.
In a email sent by the council to quote "valued partners" it questions the integrity of the study and one of the researchers and asks the recipients to keep the discussion document confidential.
Lisa Owen asked Green Building Council chief executive Andrew Eagles what he thinks of the research.