Block unwanted gaps around windows, doors, chimneys and floors to stop cold air coming in and warm air going … it could save up to £60 a year. Use window film as temporary double glazing to prevent heat escaping through the glass and, speaking of glass, closing your curtains and blinds will help stop warm air escaping through it, especially if you have radiators fitted below your windows. This will not only reduce energy use, you’ll feel more comfortable too.