Hello,

We have a late 1950 traditional red brick semi which was double height side extended 17 years ago.
It is getting ready for refurb as things are wearing out and eldest has now left home etc.

Existing windows are mainly 28mm double glazed and coated white PVC rehau units done at the time of the extension.(very badly with no sealing foam and lots of cold draughts around the frames but this is mainly sorted.)
We have well insulated loft, mainly LED lighting, draft proofed etc., heavy curtains/blinds etc. I think heat loss through doors/windows is currently about 1/4 of heat leak through the floor which is solid and original parquee and tile. We are not planning to take this up as we like it. Extension floor has 100 mm of polystyrene under it and this as it was done in 2003.

General question. Is it worth stumping up more for triple glazed rather than argon filled double glazed and could you give advice on good suppliers. We are after warm feel so we can sit by windows and areas are looking over garden and we want to be able to see it rather than masses of window frame as we do currently.
Munster, Green Building Store and Vu Fold are currently people I am going to go to.

We are after seeing out garden rather than window and door frames and a are looking for a good value frame system but it has to be very draft proof. Aluminium, wood or UPVc considered.

1 to 3 are all at back of house, West facing evening sun. All one space that ventilates together. Look of the 3 windows and doors need to gel from inside and out.

1.At the back we have a 2.4 m wide steel crittal door/ window that will not take a double glazed panel and even with secondary glazing is cold/knackered. I caulk them up for the winter and release them in the spring.
We put laminated glass in some years ago when kids were toddling and the putty has leached into the glass too.

We are looking to replace this with a large window with a seat/wooden wide ledge under after bricking up at low level.
We have ventilation elsewhere and are thinking just one great big window about 2.4 m by 1.6m high
We put laminated glass in some years ago when kids were toddling and the putty has leached into the glass too.

2. We have Rehau french doors 1.8 m wide next to a 1.1 m window in the extension dining room.
I have resealed the rubbers and still not happy they are very warm. Window is currently,where door should be as it stops sofa and table positions being in way of current walk way.

We are thinking a 2 panel sliding door with good thermal performance and narrow frame so we can see garden better.(2.9 m wide) Not seen any PVC ones with narrow enough sightline.

Bifolds I think will have too much frame for what we want them for.
Low threshold with no trip hazard preferably flat.

3. We have a kitchen sink window between 1 and 2 and would change it to match and get rid of centre of frame opening that stops me seeing the apple tree. Current window is about 1.1 m wide and left hand side opens outwards from the top, so we have to go outside to close it!
Thinking a side handle with window that tilts inwards, hinged at bottom.

Appreciate any input you can give me.

If buying new windows, then yes definitely 3G. Especially if you care about comfort: one of the main differences is that the internal glass temp is above the critical 14C dewpoint temp even when it's very cold out (given a 20C internal temp) and the radiation temp of large area of glazing is important for comfort. It also largely prevents downdrafts in front of windows. The cost increment of 3G over 2G is not large.

On the other hand, if you are not trying to get to passivehouse levels it's not crazy to replace the units in existing frames if they will take ones of decent width. A modern 2G unit can be half the U-value of a 2000 or older unit without warm spacers or softcoat low-E coatings. This avoids a load of emissions (and hassle) from new frames, so if the current ones are in reasonable nick, and you are happy with their operation, then keeping them and changing the glass may make sense. You can only get to about Uw=1.4 this way (Ug=1.1), as opposed to Uw=0.8, Ug=0.5 for good 3G, but that's still respectable, and new units are remarkably cheap.

As you get closer to Enerphit you pretty much have to go 3G in the end.

3g frames, fittings, hinges and in general ironmongery are far higher standard and quality than the majority so much more robust. I would go for a European manufacturer

My internorm windows didn’t measure as one would expect 30mm out due to a transit rail !

Fortunately I bought one ahead of the main order just in case - paid off well

Posted By: LFHello,

General question. Is it worth stumping up more for triple glazed rather than argon filled double glazed and could you give advice on good suppliers. We are after warm feel so we can sit by windows and areas are looking over garden and we want to be able to see it rather than masses of window frame as we do currently.
Munster, Green Building Store and Vu Fold are currently people I am going to go to.

Posted By: LF
Yet to go for pricing. Velfac/Internorm/Munster, Green Building Store. We will insulate under them to stop cold bridging.
Any recent supplier advice welcome.

Unfortunately, the specifications of the 3g glazing tend to vary depending on the supplier, the frame profiles they use and the style of opening. It's actually very difficult to get entirely like-for-like quotations. You'll also find varying whole window u-values. For example, I recently received quotations from many of the main self-build window suppliers, Green Building Store windows had a whole window u-value of about 0.85 and Nordvest's, the supplier I went for the averaged whole 3g window u-value came to 1. The difference in price was significant with these in that the green building store windows came to about £5k more. And with the size of some of our windows, the Green Building Store had to use a toughened glass whereas Nordvest didn't due to the frame design.

On my journey I typically found that the Scandinavian window manufacturers supply a 'standard' 3g glazing giving approximate whole window u-value of 1. The double glazed versions are typically about 1.2. Other suppliers such as Norrsken and Green Building Store specificied in my case windows which seem to be more targetted at the 'passivehaus' market and thus their 3g windows range from u-values of about 0.9 to just under 0.7. Nordan quotedme for 2g and after telling me they had a u-valueof 0.9 the details said a whole window value of 1.2.

Regarding the selection of 3g or 2g, most suppliers suggested 3g all round, one supplier suggested I go for 2g and one other supplier based in Denmark suggested 3g on all north facing windows, 2g on the south face.

I chose Nordvest windows for several reasons, one of them was the profile of the frame but overall the u-value gave me a balance between cost and performance.

The other thing that impressed me about Nordvest windows was that when I ordered them, they gave me production and delivery dates, which they kept to. They weren't pushy and salesy unlike some of the others I received quotations from. I've been installing them over Christmas and so far very happy with them.