Once in a while I get sent questions via email, to which most of them I am able to respond quite quickly with accurate information. But as you will see from the question below, this one is a bit detailed and I don’t have the necessary information to be able to answer this accurately. However, I know some of you out there probably do, and I would also like to know the answer to this question as this is something I have always wondered myself. Your answers may possible help decide for some installers whether to go down the triple glazing route or not. Answers in a comment, not on a postcard please. This question has been sent in by Adrian Green:
Maybe I am going over old ground as I don’t often read these sites, but as more and more clients ask about triple glazing I have found it very difficult to sort the facts from the fiction and give what I consider to be the best advice. I am trying to relate the potential savings with the extra cost involved and although I have asked the GGF, Pilkingtons and my usual unit supplier, none have answered with any definitive figures.
My gut feeling, and I have been making and supplying windows in the far north of Scotland for many years, is that even with our weather the extra cost doesn’t necessarily add up. North facing elevations, none opening windows on highly insulated new builds with heat recovery ventilation systems, maybe, but not as a general rule.
So can any of your technical readers equate the cost savings of say a house with say 30m2 of glazing and the difference between good double glazing with a whole window value of 1.4 and reasonable triple glazing with a whole window value of 0.8?
If any does have the calculations so we can work out the difference in the savings values between the two u-values it would be greatly appreciated, as it would be to know the time scales.
So………either the question I asked is of no interest to others or the answer could be embarrassing for the industry?????
why not do your own research and come to your own conclusions . pretty much what i do in any purchase. instead of trying to be clever!!!
I don’t think he’s trying to be clever Phil, I think he sort of knows, but wants some more specific info and to see what the rest of the industry thinks of triple glazing vs A rated windows.
I am not sure how the concept of being “clever” has arisen? I simply want to be honest with my customers and give the best advice appropriate to their needs. If the triple glazing/bigger window sections/uprated ironmongery/increased weight issues add x amount to the overall cost compared to A rated double glazed windows, what is the typical saving to be made from reduced heating bills?
Adrian, There are a number of variables (fuel cost, boiler efficiency, occupier behaviour etc.) but if we make some assumptions (15p/kW, 75% efficient boiler) you are looking at around £10 per m2 of glazing per year if you go from pre 2002 double glazing to 0.8 triple glazed, around £6 per m2 going from pre 2002 to a ‘typical’ A rated window.
Hope that helps!
The question raised is it really worth the additional cost, which can be anything from 30 – 50% higher than conventional double glazed sealed units, and does the UK weather really warrant it? probably not. It all comes down to the motivation behind it. In a conventional home you couldn’t justify the cost based on energy saving alone as the difference between double and triple would be relatively minor. However, it is known that significant reductions in noise can be had from the third pane. Installing these units into properties near major roads can increase the value of the home… Read more »
Not strictly true on acoustics Peter, a standard 28mm double glazed unit (4/20/4) achieves a dB reduction of 31, a 28mm (4/8/4/8/4) triple achieves a dB reduction of 32….If you are looking at triple for major acoustic improvements you are wasting your money. The big improvement in acoustics comes from differing glass thicknesses as different thicknesses prevent different sound frequrencies. For example, a 6/14/8.4 acoustic laminate give a 42dB reduction.
I too would like to no more.Are frames same for instance.Is it a28mm unit split into 3.Are hinges a special to hold extra weight of third pane.Are doors in range.What ar!e typical u values.For starters.I am seriously interested.
Trying to find information is hard and when you find this http://www.plumbingpages.com/featurepages/Heatloss.cfm and window U value is rated at 5.0 then window companies are not represented very well from BSI, as all windows should be below 2.0 to get a C Rating. Double glazed window can get 1.4 and with triple glazing you need Krypton to get to 0.8. Cost and visual apperance would say keep with Double Glazing
I replaced my old double glazed conservatory with a high spec triple glazed one including the roof. The conservatory faces north and is open to the house (ie no internal doors). The difference is amazing, the room is always warm and is easy to heat. It cost about 25% more than the double glazed quote but my gas bills have fallen dramtically. Also we are near a busy A’ road and noise is no longer an issue. I had trouble sourcing a wood effect 0.8 triple glazed conservatory though, it was the first one the firm had ever supplied so… Read more »
Hi JC….can you direct me to the conservatory company you used for your triple glazed conservatory…sounds exactly what I want…thanks
What company please