Curtains and blinds

Thermal curtains and blinds can help to reduce heat loss through your windows. Having your curtains and blinds open during the day and closing them just before it gets dark means your house can gain heat during the day, and better retain heat overnight. If you close your curtains and blinds on the side facing the sun and open the windows, they can also help keep your home cool in summer.

How curtains and blinds reduce heat loss

Good curtains and blinds can reduce heat loss through windows by 60% for single glazed windows, and 40% to 50% for double glazing. As they only work when they’re drawn, curtains and blinds are not a substitute for proper double glazing. The aim is to create a seal between the curtain or blind and the window, so that cold air from the window doesn’t get into the room, and warm air stays in the room.

Checklist for curtains

To provide good insulation your curtains should:

  • be made from thick, thermally-backed material
  • preferably be double layered with thick lining
  • fit tightly against the wall or window frame
  • be wider than the window frame
  • either go from floor to ceiling or have pelmets above them.

Checklist for blinds

To provide good insulation, your blinds should:

  • be specifically designed thermal blinds (sometimes described as ‘honeycomb’ or ‘cellular’ blinds) - made of two or more layers joined to form cellular compartments that trap air and provide insulation
  • have a snug fit with the window frame so that they create a good seal to trap the air in the gap between them and the window.