Triple Glazing

What is Triple Glazing?

Before we answer that, it's important to be aware that glazing and windows form the most exposed element in the building envelope in terms of energy loss.

The advent of the double glazed unit represented a significant turning point in the way glazing could be used by architectural designers. You see, by introducing an insulated cavity, and filling it with inert gas, we have reduced the "u - value" from around 5 to a point now where the minimum value now required under current Building Regulations is 1.6.

Which brings us to the triple glazed unit, which is simply a double glazed unit with an additional pane added to the construcion.

The key benefits of triple glazing are really to do with comfort. If you insulate the walls, roof and floor of a building, and you ignore the glazing, you end up with cold spots surrounding the glazing which can cause draughts and draw heat away from you if you sit in close proximity.

Another major plus is the sound reducing properties of triple glazing. The extra pane allows significant attenuation making triple glazing ideal for commercial applications or areas with high noise pollution - such as airports.

Should we switch to triple glazing?

Opinion is divided. Triple glazing is widely used in cold climate countries like Sweden and Norway, and the ultra-low energy PassivHaus standard requires triple glazed windows with a U-value of no more than 0.8. To get a window with such a low U-value, you have to not only switch to triple glazing but also insulate the frame itself, as well as using more expensive manufacturing techniques — the gas krypton tends to be used, instead of argon to fill the cavity.

The Uk has a more temperate climate so opinion is divided on this, but the pressure is on to improve the energy performance of windows and we are now reaching the stage where mere double glazing may soon no longer be enough.

Many argue that the saving gained by fitting triple glazing in offices to reduce emissions is a waste of money, because it is firstly more expensive to install, and whole life carbon dioxide emissions are increased compared to double glazing.

As energy emissions targets increase, don't be surprised to see more triple glazing in our buildings.