The supplier obligation (now termed the carbon emissions reduction target) has been set over three year cycles to allow Government to evolve the scheme so that it only pulls through products with the most potential to provide for household sector carbon emissions reductions. An independent assessment is commissioned at the end of each three year phase, building on the cost-benefit assessment undertaken and published at the launch of each scheme. Independent analysis of the three year supplier obligation scheme ending March 2008 showed it to have been extremely effective in delivery-that for every £1 added onto GB household bills to pay for the obligation, benefits equate to an average saving of £9 per household bill over the lifetime of the measures. The carbon emissions reduction target which ends in March 2011, is also believed to be highly cost-effective. We know for instance, that insulation measures make up over 60 per cent. of savings to target-equivalent to some four million households receiving insulation measures.