News comes as housing minister outlines further details of definition of zero carbon

The government has delayed making a decision on the energy efficiency levels of the fabric of zero-carbon homes until the end of the year.

The news came as John Healey, minister for housing, outlined some further details on the definition of zero carbon, which housebuilders will have to meet by 2016.

The new details include setting a hierarchy for carbon reductions beginning with high levels of energy efficiency for the fabric of the home, followed by a 70% level of carbon mitigation achieved on-site and finally a recognition that developers will need recourse to so-called “allowable solutions” such as investing in off-site renewables.

However, he said a special task group would now be set up to determine what the minimum, practicable levels of homes' basic energy efficiency should be.

The consultation document published in December 2008 offered two standards of energy efficiency. Healey said today: “Respondents welcomed the proposition that energy efficiency should be the first priority, although many argued that the standards quoted were not suitable as a minimum regulatory standard to apply to every new home in England and that we do not have an appropriate established energy efficiency standard for the purpose of zero carbon homes”.

Healey said he accepted this and would wait on the task group's report before announcing what this should be.

Stewart Baseley, executive chairman of the Home Builders Federation, said: “Companies are still working on how to achieve the proposed changes in Building Regulations on energy efficiency in 2010 and 2013, which are equivalent to the energy requirements of levels three and four of the Code for Sustainable Homes respectively. The government's ambition for a 70% improvement on current standards delivered on-site using renewable energy technology from 2016 would be a further major step beyond that.”

Paul King, the UK-GBC chief executive, responded positively to the announcement. He said: “This announcement confirms a sensible “hierarchy” approach to carbon reductions.”

He added that it would provide increased confidence for an industry that needs to plan and deliver urgently needed new homes. “But the final definition remains very important and we look forward to that in due course.”

Full details on the definition will be announced at the end of the year.

Healey's statement is available at: