New homes will become "zero-carbon" by 2016 by tightening energy efficiency requirements, the DCLG declared this week.Under proposals unveiled for consultation, energy performance in the building regulations should improve by 25 per cent by 2010. Three years later, homes will have to be 44 per cent more energy efficient and by 2016 all new homes must be zero-carbon.A home will have to produce all its own energy, but if it takes some from the national grid it will pay it back at other times of the year, according to the government. Communities secretary Ruth Kelly said the proposals will cut around 20 per cent of housing emissions by 2050.The final code for sustainable homes was also published this week. House builders will have to provide buyers with green star ratings for new properties from April 2008. WWF-UK campaigns director Paul King said: "The code sends the right signal for house builders to put zero carbon at the top of their agenda."T...