C+ Energy rated windows can save you money, but make sure you buy quality to last.

A double glazed unit is expected to last up to ten years, but if it fails, the cost of replacing a sealed unit that has misted up will far outweigh the potential energy savings and subsequent environmental impact.

Don't get blinkered into thinking that an 'A' rated window is necessarily the best quality.

In an average home fitted with 'C' rated windows, the energy loss amounts to £9.50 worth of energy per year. Compare this to the same home currently fitted with 'F' rated windows and the loss amounts to £60 per year. Over a ten year period this saving becomes more significant.

An 'A' rating means that there is theoretically no energy lost through the window. This extra saving is great, but insignificant if a glazed unit fails due to poor quality. The actual cost of replacing just one sealed unit would be more than the theoretical energy lost over a decade in a house fitted with 'C' rated windows that experienced no failures.