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Curtains and blinds

Thermal curtains and blinds can significantly 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 retain some of that heat overnight.  They can also help keep your home cool in summer if you close your curtains and blinds on the side facing the sun and open the windows

Good curtains and blinds can reduce heat loss through windows by 60% for single glazed windows, and 40-50% for double glazing.  Of course, as they only work when they are drawn, curtains and blinds they are not a substitute for proper double glazing.

The main thing you’re trying to achieve with curtains and blinds is a good seal that will prevent warm air from getting behind the curtain or blind, and also stop colder air between the curtain or blind and window from getting into the room. 

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.

To provide good insulation, your blinds should:

  • be specifically designed thermal blinds (sometimes described as ‘honeycomb’ or ‘cellular’ blinds).  These are made of two or more layers joined to form cellular compartments that trap air, providing 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.