I am trying to find some figure to be used in a cost analysis of new double vs new triple glazed windows.
Given many people have had upgrades to their glazing. I thought some people would be willing to help.
If people could list the following elements it would be extremly useful, for myself, but also others looking to upgrade. I have given an example of my last window purchase. Hopefully there’s more up to date pricing then my example. Any info is useful.
Year- Month -Cost/m2 - Frame type - Glazing type - Gas infil - Spacer bar type - Supplier - Any info on U value. - other info
2020 - October -£146.8 inc VAT - PVC - triple glazed - Argon - thermobar - Epwin windows purchased from Kingfisher windows -Uw elegidly 0.8 -price includes 1 front door and one fully glazed back door.
Yeah the U vaklues for those units @Eric_Fewster would be great.
@Christian_Unger The Uwindow value claimed by the manufactuer in my initial example (PVC) was 0.8 Which is of course fantastic. I was very hesistant to believe it as they could not provide me with evidence of Uframe seperately. The glazing was apparently 0.5
Doing the calcs myself and with the glazing fraction, the Uframe value would be 1.47
Given they were PVC i was not expecting the airtighness to be good and they infact had no data on it.
But you can see i paid very little for the units. In this project i was willing to make that trade off.
Wow i am a little bit shocked at the prices. Of course I expect timber frame PH certified units to be expensive. But these makes the price paid for my windows example an absolute bargain?
Do you consider trying to simplfy the opening types.
For example instead of sliding patio doors, use fully glazed casment doors, they are considerably cheaper and alot more airtight.
And being satisfied with normal casement or top hung, instead of tilt and turn which are of course a lot more expensive.
At the moment I am still shopping around more though and I would prefer tilt and turn. It is the standard in Germany and I can’t really see why that would be much more expensive. I thin the price is higher for timber windows and because they have the passivhaus quality credentials you may not get everywhere.
Anyway, you are right on the sliding door and I am also looking at that a bit more carefully and consider other options to replace it with. Will need to do a bit more thinking on that first consider light in the room and even potentially solar overheating.
The thing I also just noticed as that 21 degrees specifies the Sills for the door as Part M compliant with thermal break, which wasn’t specified for the NorDan door above.
Anyone knows what to look out for there? I was thinking about how to ensure no cold bridges under the door and my architect talked about some structural foam underneath. Is that what is already included here you think? Would the door installers consider that? Thanks.
I had all my doors and windows replaced by Green Building Store (now 21 degrees) in 2017. The prices may well have changed by now, but then there was nothing at all to get close to them on a price and quality analysis.
I had their triple glazed wooden windows in the Ultra range which are passivhaus equivalent but not certified. u value of glass is 0.52 and overall 0.75 I think.
Have been absolutely delighted with them.
Yeah windows in these cases were simplified, try to normally steer away from sliding doors as they tend to be double the cost per m2 (and also can have airtightness issues as you say).
OK, with the caveat that there are loads of factors that change things, here’s my example to give an indication. They’ve been super helpful & patient in working out the detailing, which is not simple, so I consider that really valuable.
Viking Windows, high performance wooden, installed by Retrofit Windows.
2025, LowE glass, argon filled. Made in Estonia.
Double glazed ~£500/m2 incVAT
Any colour from the RAL colour chart.
U-value 1.3
I have just been on the EPC website and one of the recommendations for my house was to upgrade the windows. However, the cost they suggest for this was only £5500… I guess PVC double glazed must be less than half the price of the triple glazed timber windows and doors. I got 10 windows and 3 doors in my 80sqm semi-detached 3-bed house… including 2 bay windows. From the quotes I had so far I will be above £20000 if I want to replace all of them with triple glazed timber windows.
I read somewhere that triple glazed is only 10% more, but if I take the recommendation from the EPC website these windows are more than 4x more and this is not the most expensive brand. Pretty crazy. Why am I such an eco freak?!
Will anybody who may buy the house in the future even notice that these are so excellent windows? Sigh.
I am still waiting for retrofit windows to call back, but they emailed me and they are not too far from my place in Crewe. When you are saying it costs about £600 per item to install, would that include doors or are they more work? I am trying to get around install costs at the moment and the below was so high. What would you think to consider for 2 windows and 3 doors on the ground floor? Thanks.
You’re looking at premium quality products, though. Don’t make me break out the car analogies…
I’ve no idea what “normal” uPVC costs these days. But also bear in mind EPC recommendations have been pretty wildly optimistic in the past. Who remembers the £1000 floor insulation estimates a few years ago?
From my experience, yes they’ll notice them but you probably won’t make the money back. But it’s hard to tell - they add to the “feel” of a house and if you get the right buyer…
