THESE images reveal just how much energy we lose through poor and outdated roofs, glazing and window frames.
Homes, offices and shops were targeted with a thermal imaging camera to find out how much heat escapes.
Office blocks were found to be repeat offenders thanks to open staircases, large glazed doors and fire escapes.
White designates the hottest areas — where most heat leaves — cooling down to orange then blue.
Wooden front doors were found to be an energy drain, and thatched houses lose masses of heat where the gables meet the roof.
Julia Berkin, of glass maker Pilkington, which compiled the images in the city of Coventry, said: ‘Over years or decades, those little bits of heat leaking out will add up to have a huge impact on your energy bills.’