The energy efficiency of windows is measured with a ‘u’ value and the lower this value the better. Single Glazing has a value of 5u, older double-glazing about 3u and new modern double glazing a u value of 1.6u. Triple glazed energy glass has a value of 0.7u which is very close to that of insulated walls (0.5u).
The triple layer of glass with the cavities reduces the conduction of heat and so greatly reduces heat energy loss. An inert gas like argon fills the interior spaces between the glass panes as it does not conduct heat as quickly as air. The same technology can be applied to doors.
Triple glazing also significantly reduces noise and so is ideal for those living in noisy areas.
Double glazed windows also offer energy efficiencies and noise protection but to a lesser degree. Your home can still be rated as category ‘A’ with double glazing but for many homes, once we have done the savings calculations, triple glazing would be more cost effective over 10 years.