We welcome the approach taken by the UK Green Building Council to lobby for a change in the definition of zero-carbon homes (20 November, www.building.co.uk).

The National Federation of Builders has long argued that zero-carbon homes cannot be achieved by builders alone, as it requires a massive input of renewable energy from the supply industry. Our members do and will continue to build energy-efficient homes, but we’ve been concerned for some time that the responsibility for delivering renewable energy has not been properly allocated.

Government ministers have developed an exaggerated understanding of what can be achieved by housebuilders. The debate must now concentrate on scaling back their expectations to reasonable levels.

Roger Humber, housing spokesperson, National Federation of Builders