the certificate provides a to g ratings for the building with a being the most energy efficient and g being the least the current average score for the uk is around a d from the eu energy performance of buildings directive will also require all home sale advertisements to have an energy efficiency rating established to complement cert this scheme achieves aims of both carbon reduction and addressing fuel poverty by requiring energy suppliers to achieve million tonnes co lifetime savings in the most deprived areas of england scotland and wales promoting areabased and wholehouse approaches to energy efficiency improvements