In the UK, double glazing has been the standard for window installation since it was introduced in the 1970s. Triple glazed windows only have a small percentage of the window market in the UK and do not have the same uptake that is seen in Europe and Scandinavia.
So, why hasn’t triple glazing had the same uptake, so far? We look at the advantages and disadvantages of triple glazing to see if they are the right option for you and if you might be missing out.
Advantages of triple glazing
Triple glazing has three panes instead of two for double glazing. The big difference between double and triple glazing is that the triple glazed unit has two air gaps, not just one, to reduce thermal transmission. Twice the air gaps of double glazed units and twice the buffer against cold air.
Superior thermal performance
The primary selling point of triple glazing is the superior energy efficiency. Standard double glazing windows have a WER rating of A, with A+ being the best rating on offer. Triple glazed windows achieve A++ rating for their efficiency.
The difference in U-values that measure heat transmittance represents how much more efficient having an extra pane of glass can be. Triple glazing is 23% more efficient with a Uw rating of 1.0 compared to 1.3 for the best double glazing. Upgrading from old double glazing to triple glazing can expect 58% more energy efficiency.
Building regulations currently require replacement windows to have a minimum U-value of 1.4 W/m2K. In the push to make housing more energy efficient to meet climate change targets, the U-value could be reduced again in the future.
Keeps heat in
In Scandinavia and parts of Europe, triple glazing has a market share of 60%. For cold weather climates and north facing windows, triple glazing is recommended to keep the cold air out and retain the warmth in a room.
Keeps heat out
Insulating air gaps between panes of glass not only keep cold air out, they can also help to keep rooms cooler in warm climates.
The G-value measures how much solar gain is transferred through a window. A higher number means that more solar gain can pass through and a lower number means that less solar radiation can pass and the room stays cooler.
Additional panes of glass in triple glazing reduce solar gain which means that less radiation from the sun is transferred into a room and can help to keep a room cooler.
Reduced condensation
Condensation forms on window panes when excess moisture in the air collides with cold surfaces. Windows are prone to condensation when it’s colder outside than inside.
Excessive condensation should not be ignored as it can result in harmful mould that is significantly bad for health.
To get rid of condensation, ventilation is needed. However, double glazing reduces thermal transmittance, so that the inner pane of glass is not as cold as the outside and moisture doesn’t form. Triple glazing can reduce the cold on the inner pane of glass even more with its super thermal efficiency, resulting in less condensation on the inside of windows.
Additional security
Because triple glazing has three panes of glass, it is more difficult to break through a window fully. This makes it more secure against intruders.
For the best protection, fusing a PVB layer into a pane of glass creates a laminated layer and this has the benefit of holding the glass together if it breaks. This is useful for glass in rooflights or for glass in doors and secluded windows that need extra protection.
Everest triple glazing has a toughened inner pane of glass with the option for a laminated glass pane in our triple glazed units.
Could increase property value
The focus on energy efficiency for housing in the UK means that there’s an emphasis on houses that have a high EPC rating.
All buildings in the UK are rated between G (lowest) and A (highest) as a measure of how energy efficient they are. An EPC certificate is required when renting or selling a property.
There is a proposal to introduce legislation that all rental properties be increased from E-rated to C-rated from 2023.
This emphasis on the higher EPC rating means that houses that are A, B or C rated will become more desirable for sale and potentially have more value.