Test it yourself !

With the use of a lighter or a candle you can establish if you have low energy coating on your double or triple glazed windows.

Hold the lit lighter or candle up towards the glass either when it is dark outside or against a dark background. In certain cases you will have to do this from both inside and outside. Look at an angle against the glass.

If you have double glazing you will see a mirror image of 4 flames, two in each glass. Each glass surface gives 2 mirror images of a flame. If one of the flames has a different colour, then you have one glass with low energy coating. The U-value of your glazing unit is then likely to be below 1.8, without the low energy coating, 4 flames the same colour, the U-value is likely to be 2.8 or higher.

If you have triple glazing you will see the mirror image of 6 flames. If one of the flames has a different colour it is likely you have triple glazing with a U-value of 1.5. If you have a modern triple glazing unit with 2 flames of a different colour, you are likely to have a glazing unit with a U-value of 1.1 or lower. A triple glazed unit without low energy coating, all 6 flames the same colour, will have a U-value of 1.9 or higher.

Make a note of your U-values and try Broxwood’s window energy calculator to find out how much you can save if you change your windows and doors.