Try our energy saving calculator - simply select your property type and the conditions that best match your home.
Our calculator is based on that produced by the Glass and Glazing Federation (GGF) which has been approved by the Energy Saving Trust (EST). It works out the heat flow through a standard window comparing your existing glazing with a range of alternatives to see how much heat you can retain.
Calculations are based on standard house types with an assumed area of glazing. The starting points are either single glazing in a timber frame or double glazing in a timber frame, consisting of two panes of uncoated 4 mm glass and a 6 mm airspace.
Savings are based on gas heating with average efficiency over a 20 year period allowing for fuel price inflation.