Over the last 12 months, we’ve seen an massive increase in the number of customers asking about the possibility of adding triple glazing to their windows and doors project.
These days homeowners and architects are always looking for ways to achieve better energy efficiency, and more and more glazing suppliers are manufacturing triple glazed products to cater for this demand. These factors have combined to reduce the cost of triple glazing to the point where it has become a fairly affordable cost upgrade from standard double glazing options.
So on the face of it, it finally seems to be an easy decision to add ultra high performance triple glazing to your home extension or new build. However, the cost of the glass is not the only factor you need to consider when choosing between double and triple glazing.
Can your window frame accommodate the extra width?
Our double glazed IG (insulated glass) unit is constructed of a pane of Low-E glass 4mm thick, then a 20mm air gap (commonly known as a spacer bar), then another piece of glass. So the total width of the glazing unit is 28mm.
Although the best performing air gap (spacer bar) between glass pieces is 16mm – 20mm for double glazing, triple glazing typically uses shorter spacer bars in order to reduce the overall width of the unit. So our standard triple glazed IG unit has the three pieces of 4mm glass separated by two 12mm spacer bars.
This comes to a total width of 36mm (8mm thicker than double glazing), and with argon gas and warm edge spacer bars as standard this triple glazing unit achieves a Ug Value of 0.9 W/m2K. That’s a 25% improvement in thermal performance over its double glazed counterpart.
We also offer an even better performing triple glazing IG unit with 16mm spacer bars – which comes at 44mm thick and has an amazing Ug Value of just 0.5 W/m2k.
However, not all window systems are able to accommodate this extra width – so if you want to go for this level of specification on your glazing you must look closely at the makeup of any unit you are offered or are thinking of buying.
Triple Glazing is 50% heavier than Double Glazing
Related to the width issue is the window system’s ability to support the sheer weight of triple glazing. 50% more glass results in 50% more weight – and it means that your average 4mm triple glazing IG unit weighs in at a staggering 32.25kg per square metre.
So the triple glazing in an average 6ft x 4ft living room window (2.2m2) weighs 71kg, compared to 47kg for a double glazing unit of the same size. That’s going to put a significant strain on the window frame and other hardware such as hinges.
And if you are going for a real Grand Design, remember that 4mm glass can only be made up to a maximum panel size of 1,300mm x 2,440mm – any larger than that and you’ll need to move up to 6mm thick glass. That’s another 50% increase in the total glass weight in your window frame: our 71kg unit would then tip the scales at just over 106kg.
It’s not just your frames that must be top quality
So it’s clear that for triple glazing you need premium quality window hardware – especially at the larger sizes demanded by really stunning modern and airy designs.
However, it is not only your choice of window system that you need to focus on; there are other factors that will determine the cost and feasibility of your new triple glazed windows.
Like most glazing suppliers operating in the UK we are required to ensure that our employees – including loading staff, delivery drivers and installation teams – are able to safely and comfortably handle large and heavy glass units at all times.
As a general rule of thumb we will not allow any glass unit weighing more than 100kg to be manually handled by any of our staff. Units above this weight cannot even be manufactured without specialist equipment, which naturally adds further costs to your project.
We have invested heavily in glass lifting robots to improve our manufacturing and enable us to produce these monster sized pieces of glass. And we regularly call upon crane companies to help us to safely install them at our clients’ sites.
When Grand Designs go wrong
And the grander the project, the more likely the chance of hiccups. Recently we were working on a project in the Lake District on a stunning house overlooking beautiful Lake Windermere. When we arrived at the property on installation day we found that the scaffolding still being used by other tradesmen was obstructing the huge window spaces!
Naturally our client was keen to make their property watertight as soon as possible – so much of the scaffolding had to be taken down and rebuilt to allow the glazing to go in as scheduled.
As a homeowner or architect you must take these potential costs and complications into account when designing your dream home with large, energy-efficient triple glazed windows – but I can assure you that the end result is always worth it.
So to sum up, triple glazing offers unbeatable energy efficiency but it will add significant extra weight and size to your windows – so you must be sure that the frames you purchase are designed well enough to comfortably accommodate it. And remember in your planning that this extra weight can also cause logistics problems and incur unforeseen costs at installation time.
At Luxal, we can solve all these issues: we manufacturer several high quality window systems capable of easily supporting the dimensions and weight of triple glazing at any size – and of course we have a 10 Year full warranty to prove it.
And you can also rely on our 15 years’ experience in the manufacture, handling and installation of glass panels, windows and doors to ensure that everything will go smoothly on installation.
If you have any questions about the impact of choosing triple glazing for your extension or new build, please leave a comment below or call us on 0203 00 22 088.