Single glazed windows can have a U value of around 5.0W/m²k Double glazed windows used to score over 3 and can now achieve 1.4 (Velfac have 1.36). As a result of these improvements in the manufacturing process, Building Regulations now insist that any window you install today should have a U value no worse than 1.6 The Passivhaus standard requires triple glazed windows with a U value of no more than 0.8 but there are some suppliers who claim to achieve just 0.5 The U value demanded for walls is currently less than 0.3 so you can see that windows remain weak spots in the overall thermal efficiency of a building envelope. Hence the tremendous pressure to improve their performance even further.
James looks like he had a very good Christmas.
Single glazed windows can have a U value of around 5.0W/m²k
Double glazed windows used to score over 3 and can now achieve 1.4 (Velfac have 1.36). As a result of these improvements in the manufacturing process, Building Regulations now insist that any window you install today should have a U value no worse than 1.6
The Passivhaus standard requires triple glazed windows with a U value of no more than 0.8 but there are some suppliers who claim to achieve just 0.5
The U value demanded for walls is currently less than 0.3 so you can see that windows remain weak spots in the overall thermal efficiency of a building envelope. Hence the tremendous pressure to improve their performance even further.
DON,T BOTHER CLIMATE IS HOTTING UP SO WON,T WASTE MY MONEY ON INSULATION THATS MY OPINION.