What are the benefits of Triple Glazing?
A Triple Glazing style Window, as the name suggests, consists of three panes of glass each separated by an air gap. These air gaps provide the insulating layers which reduce heat loss and prevent condensation.
The effect of this additional layer is that the Triple Glazed window is significantly better than double glazing.
The energy saving is increased as Triple Glazed Windows are considered to provide 60% better insulation than a low-e argon filled double glazed pane and the radiation heat transfer between the glass and the room is said to be 80% less.
Currently, the use of Triple Glazing in the U.K is limited and fitting it is considered by some to be ‘overkill’. Not surprisingly it has found greater use in colder climates particularly within the Scandinavian countries and North America.
The cost of providing the additional panes of glass is in the order of 50 % more than the cost of a double glazed unit. Having regard to the less cold weather conditions in the UK it is perhaps necessary to ask whether the benefits achieved warrant the additional expenditure involved. If you were to compare the financial savings accrued from fitting triple glazing, it is clear that despite obvious performance improvements, the savings are such that the additional expense may not be justified.
Substantial arguments have been put forward to justify triple glazing in the belief that attaining a higher comfort level is the main benefit by maintaining a steady temperature. Wolfgang Feist at a conference in Oxford produced a table showing what the temperature differences were close to different forms of glazing when the internal temperature is designed to maintain at around 21°C and the external temperature drops to —5°C.
- next to a single glazed window, the adjacent temperature would be expected to be around 1°C
- next to a double glazed window the adjacent temperature would be around 11°C
- next to a high specification low-e double glazed window, the adjacent temperature would be 16°C
- whilst next to a triple glazed window, with a centre pane U value of just 0.65, the temperature is 18°C.
We can see from these figures that there is an improving situation. These improvements need to be judged against the relevant cost of the increased specification of each system.
Where noise is a factor in considering the use of Triple glazing such as a building situated near a busy road or under the flight path of a busy airport then the increased expenditure may be justified as the level of noise is reduced significantly.
The thickness of the glass used is one of the key elements of the level of sound insulation. Each thickness of glass will block out a different frequency, so a combination of panes of different thickness is very effective at keeping noise out. This is known as asymmetrical glazing. It should be mentioned that even the weight of the glass plays a part since the compact mass reduces sounds.
A second key element is the size of the gap between the panes. The larger the gap, the better the overall sound insulation effect. So by having a second gap, triple glazing has a clear advantage over double glazing.
When considering the use of double or triple glazing therefore what should be borne in mind is that Triple Glazing has obvious advantages over Double Glazing in terms of energy efficiency. It has an even greater advantage when it comes to noise insulation.