Double glazing has come on in leaps and bounds from its introduction years ago. We all noticed the difference that double glazing made back then - no draughts, maintenance free frames and much quieter houses.
These days with the lates generation of energy rated windows, the difference is quite amazing. So little heat is transmitted through the latest 'A' rated window units that it is quite common for condensation to form on the outside of the windows in the right conditions. This is a good sign, not a fault, as your hard earned heating is not being transmitted to the outside pane of glass.
Savings of up to £460 a year can be made having these windows fitted and over the life of the windows, they will certainly pay for themselves.