The energy giant said that the conclusions have come from a study conducted by property data platform Sprift that looked at energy performance information on 25 million UK households. The research concluded that some 45 per cent of surveyed buildings were meeting outdated building standards, according to the company. EDF said that a failure to account for more modern materials and standards around energy performance was potentially costing many of these households more money for their heating. EDF said it had also commissioned a survey of 2,000 UK homeowners as part of the study to look at attitudes to insulation improvements in homes. The insulation programme is supported by the Energy Company Obligation (ECO) and aims to assist 700,000 properties to help households access efficiency improvements.