<p>The extra cost of building a zero carbon home has halved according to a new study from the Zero Carbon Hub.</p> <p>The analysis, carried out by the Sweett Group, looked at the extra cost of building to the proposed zero carbon standard compared to Part L 2013. It found that the typical additional cost of building a semi-detached house to the zero carbon standard could be less than £5,000 at today's prices. This compares to nearly £12,000 the last time it was calculated in 2011 when costs were compared with 2010 regulations.</p> <p>The Hub says there are several reasons for the reduction including cheaper solar PV, changes in the zero carbon definition and greater efficiency in meeting air tightness standards. </p> <p>Zero Carbon Hub md Rob Pannell said: "What this report shows is that the zero carbon policy, while ambitious, is becoming more cost effective. The challenge is to continue innovating to keep costs as low as possible."</p> <p>The report finds that by 2020 the extra cost for a semi-detached home could be less than £3,000.</p> <p>HBF director of external affairs John Slaughter said: "While predicted costs are lower than previously estimated, they remain significant. This is still a challenging …