Keith Anderson.Kingspan Insulation has expressed concerns that discrepancies in energy rating software tools are misrepresenting product performance and misleading consumers and building professionals.

It says lack of calibration between software employed by energy assessors is leading to inconsistent energy assessments for new homes, allowing builders to cherry pick the software program likely to give a better result using, and in some cases, inferior product solutions.

Kingspan Insulation technical manager, Keith Anderson, says since the Nationwide House Energy Rating Scheme NatHERS) moved from 5 star to 6 star minimum requirements, it is becoming increasingly important to ensure a consistent, accurate framework for assessments.

"We are finding discrepancies of up to a whole star unit when modelling reflective insulation under a roof against a bulk insulation of similar theoretical R-value," he says.

"As a result, home buyers are being disadvantaged through higher later costs for heating or cooling a home, reducing genuine environmental benefits and diminishing government efforts to reduce carbon emissions.

"Both state and federal government need to guarantee the integrity of the scheme, particularly as energy efficiency, reduction of greenhouse gas emissions and the importance of insulation become increasingly prominent issues."

Kingspan says the issue of discrepancies has been particularly pronounced in Queensland, where a commonly used software package is inconsistent with the agreed standard AccuRate.

Anderson believes tighter rules regarding calibration of software should be required to achieve Building Code of Australia compliance.

"NatHERS is running tests between software at present but it may be six months before current provisional accreditations are finally assessed," he says.

"We’d like to see immediate changes to how energy rating tools are accredited and a restriction enforced on the use of non-compliant rating tools.

"These changes would ensure a system that guarantees energy efficiency in the residential housing market is truly achieved."