Cost effective total window replacement

[Ommm]

I'm wondering how to approach a project where I need to replace all of the 1970s/80s aluminium double glazed windows of a property in south west Surrey.  The main problem is there are lots of windows and some of them are large, and I want to do it to a reasonable thermal spec (lots of glass area = heat loss) while on a limited budget.  To give an idea, there are 11 windows and 5 doors (inc 3 sliding patio doors) - the doors are roughly 2.4m x 2m and the largest window is 3m x 1.2m.

 

To keep the budget under control I'm probably looking at uPVC. What might be options for suppliers?  I can of course ask the local firms around to quote, but I'm wondering if there's any good value 'IKEA' or 'DIY Kitchens' kind of fabricators who I can source the windows from and then find someone to install (I know someone who might do it). I know there's plenty of 'buy windows online' kind of places but I don't really know who are good companies beyond just random Googling, and many of the quoting tools don't say who makes the profile they're using so it's hard to gauge quality.

 

There used to be a window factory down the road but it's now a block of flats...

[JohnMo]

Trouble with most windows you mostly get what you pay for. Argon filled double glazing is argon filled glazing, the frame design is the difference between a a good window and a poor one. So when comparing look at the U_w that is the U value of the whole window, not just the glazing (U_g).

 

Also make sure the installer is filling the void around the window, ideally with an airtight foam. Lots fits window and just cover the void circumventing a decent U value.

 

 

[Gone West]

55 minutes ago, Ommm said:

What might be options for suppliers?

I have used Modern UPVC Windows for both windows and doors and not had any problems. I think they are good value for product and service. I did fit them myself though.

 

https://www.modernupvcwindows.co.uk/

 

Edited August 9 by Gone West

[Tony L]

A friend has used this company twice & has been pleased both times.  They've just fitted a long bi-fold run, separate slide or French patio doors (can't remember which) & 6 or more other doors/windows to his house extension.   They supply & fit.  

 

https://truglaze.co.uk/  They're in Frimley Green, so probably not far from you.

 

Please let us all know how you get on - I have a rental property that will need new windows within months (assuming the tenant moves out, as expected).

Edited August 9 by Tony L

[gaz_moose]

just chucking them in yourself might cause an issue when you come to sell it as you wont have a fensa certificate.

 

you can use websites like, modernupvcwindows to get an idea of what you want then an idea of cost before you get some quotes.but dont forget the installer will price in trims/foam/silicone/packers/fixing etc.. 

 

i have eurocell in my house because they are round the corner from me and noise reduction Liniar in my garage because i got them off marketplace off some crackhead. I put a crystal from the bargain bin section in wickes in my mates garden room/playhouse because it was £20.

 

These is a quite a bit to it and once you take your old one out you have to get the new one in by the end of the day or it gets chilly. 

 

 

[Oz07]

Which are the best upvc profiles? They all claim to be! @craig

[craig]

5 hours ago, Oz07 said:

Which are the best upvc profiles? They all claim to be! @craig

For me, Aluplast, specifically the Energeto 8000. Is it the cheapest? No.

[Oz07]

5 hours ago, craig said:

For me, Aluplast, specifically the Energeto 8000. Is it the cheapest? No.

What makes a better profile?

[Gone West]

13 hours ago, gaz_moose said:

These is a quite a bit to it and once you take your old one out you have to get the new one in by the end of the day or it gets chilly. 

I just screw a bit of OSB in the hole and finish it the next day, and don't do it in mid-winter.

[craig]

3 hours ago, Oz07 said:

What makes a better profile?

The amount of chambers, welds, material used (polybutylene terephthalate (PBT) engineering plastics rather than steel for strengthening and thermal improvements

Edited August 10 by craig

[craig]

.

Edited August 10 by craig

[Oz07]

15 hours ago, craig said:

For me, Aluplast, specifically the Energeto 8000. Is it the cheapest? No.

Just looked. Glued glass to sash. Must be expensive if unit fails or gets broken? I think that would put me off

[craig]

2 hours ago, Oz07 said:

Glued glass to sash.

Very easy to replace, obviously not as easy as glass into the frame without glue but it's a security thing as well. Doesn't take much longer to remove the glue, clean and put new unit in with the glue. It's also an extra, not standard.

Edited August 10 by craig

[craig]

What do I use when it's a cost thing?
 

• Aluplast Ideal 4000 (Double)
• Aluplast Idea 8000 (Triple)

Alternatively I would look at Rehau, Gealan or Salamander.

Edited August 10 by craig

[Ommm]

Thanks all. Modern UPVC Windows look handy as they have a configurator thingy - as changing the setup is possible (fewer panes per window than currently) it'll be useful to experiment with. Then I have a spec I can pass around to others. I know a Proper Window Installer, I'm not going to be DIYing this.

 

Craig, also good to know some systems worth looking at. I'm still at early stages yet but might give you a ping when things have come together a bit more. 

 

A few things I was wondering. Modern Windows only do double glazing for sliding doors - triple is too heavy apparently. But their glass is only U of 1.22 - and these are the biggest windows where it matters the most. Apart from going to folding doors, which I'd rather avoid, is there any way to improve the U value?

 

Also pondering what to do about shading on the south (street facing) side. Solar gain is brutal with these large windows. Should look at integral blinds as shutters might be complicated...

 

Other suggestions of suppliers to look at very much appreciated...

 

 

[Oz07]

20 hours ago, craig said:

Very easy to replace, obviously not as easy as glass into the frame without glue but it's a security thing as well. Doesn't take much longer to remove the glue, clean and put new unit in with the glue. It's also an extra, not standard.

Do the installers glue the unit in when window fitted then or do they come factory glued?

[craig]

1 minute ago, Oz07 said:

Do the installers glue the unit in when window fitted then or do they come factory glued?

Factory glued but also done on site when required, as sometimes you need to fix through the frame and glass needs to be supplied loose.

[craig]

Double glazing at 1.2Ug, isn’t bad at all but expected Ug now for double glazed. I can only suggest getting a system that can handle the weight. 

[scottishjohn]

On 11/08/2026 at 10:58, Ommm said:

Thanks all. Modern UPVC Windows look handy as they have a configurator thingy - as changing the setup is possible (fewer panes per window than currently) it'll be useful to experiment with. Then I have a spec I can pass around to others. I know a Proper Window Installer, I'm not going to be DIYing this.

 

Craig, also good to know some systems worth looking at. I'm still at early stages yet but might give you a ping when things have come together a bit more. 

 

A few things I was wondering. Modern Windows only do double glazing for sliding doors - triple is too heavy apparently. But their glass is only U of 1.22 - and these are the biggest windows where it matters the most. Apart from going to folding doors, which I'd rather avoid, is there any way to improve the U value?

 

Also pondering what to do about shading on the south (street facing) side. Solar gain is brutal with these large windows. Should look at integral blinds as shutters might be complicated...

 

Other suggestions of suppliers to look at very much appreciated...

 

 

get three quoted and treat sales spiel with some caution 

 

but by the time you have 3 quotes you should have an idea of what you want and price range

 

 triple glazing is only really to deaden outside noise difference in heat loss is minimal

Edited Thursday at 11:16 by scottishjohn

[craig]

6 hours ago, scottishjohn said:

triple glazing is only really to deaden outside noise difference in heat loss is minimal

 

That's not really correct.

 

Triple glazing isn't primarily about reducing outside noise, its main advantage is improved thermal performance. A typical modern double-glazed unit might have a Ug-value around 1.0–1.2 W/m²K, whereas a good triple-glazed unit can be around 0.5–0.7 W/m²K, so the heat loss through the glazing itself can be roughly 40–50% lower.

 

That doesn't mean your heating bill drops by 40–50%, because windows are only one part of the building's overall heat loss. Interestingly, triple glazing isn't automatically better acoustically either. For noise reduction, the thickness and combination of the panes, cavity widths and especially acoustic laminated glass can be much more important. A properly specified acoustic double-glazed unit can outperform a standard triple-glazed unit. So there are perfectly valid arguments about whether the additional cost of triple glazing is worthwhile for a particular property, but saying the thermal difference is minimal and triple glazing is mainly for noise isn't really accurate.
 

[Oz07]

1 hour ago, craig said:

 

That's not really correct.

 

Triple glazing isn't primarily about reducing outside noise, its main advantage is improved thermal performance. A typical modern double-glazed unit might have a Ug-value around 1.0–1.2 W/m²K, whereas a good triple-glazed unit can be around 0.5–0.7 W/m²K, so the heat loss through the glazing itself can be roughly 40–50% lower.

 

That doesn't mean your heating bill drops by 40–50%, because windows are only one part of the building's overall heat loss. Interestingly, triple glazing isn't automatically better acoustically either. For noise reduction, the thickness and combination of the panes, cavity widths and especially acoustic laminated glass can be much more important. A properly specified acoustic double-glazed unit can outperform a standard triple-glazed unit. So there are perfectly valid arguments about whether the additional cost of triple glazing is worthwhile for a particular property, but saying the thermal difference is minimal and triple glazing is mainly for noise isn't really accurate.
 

Interesting. I'm sure when I looked into it the cost difference of triple glazed windows was never going to pay back the energy savings over double in the life of the windows. Unlike single glazed to double where they do save you money. The improvement wasn't as drastic with 3g vs 2g. That rules them out for me although @JohnMo said it was more a comfort thing. 

[JohnMo]

1 hour ago, craig said:

Ug-value

But that is a pretty meaningless value because it doesn't include the effects of a good or poor frame.  U_w gives a way better comparison, then you know what you are getting.

 

8 hours ago, scottishjohn said:

triple glazing is only really to deaden outside noise difference in heat loss is minimal

Sorry a throw away statement above, it really depends on window size.  We have 6m wall of glass, this results in this room loosing more heat that the rest of the house put together.  Our window U_w is 0.8, compared to good double glazed being nearer 1.2-1.4, so around 40% heat loss for that wall.

[craig]

1 hour ago, JohnMo said:

oesn't include the effects of a good or poor frame.  U_w gives a way better comparison

 

Of course, you are correct but I was talking specifically about glazing on the assumption of a good frame but never qualified that point.

[Mike]

A key benefit of triple glazing is that the inside air temperature next to the glass will be a few degrees higher than it would be next to a similar double glazed unit. If you have underfloor heating, then the closer that temperature is to the target room temperature, the slower the convection currents are in the room. Which creates a more uniform temperature gradient from floor to ceiling, so you don't need the thermostat as high (which is where there's a cost saving). It also removes condensation risk even when temperatures drop well below zero.

 

However, if you don't have UFCH then the first of these benefits goes 'out of the window' as you'll have significant convection currents anyway. And if you do have UFCH + well-specified double glazing (argon filled, low-e, good weather seals, well-insulated frame), then the temperature gradient can still be very good.

 

In short, it's preferable to choose double glazing in a well-insulated frame, rather than a triple glazing in a standard / poorly insulated frame. U_w is the best guide for that.

 

Edited Thursday at 21:19 by Mike

[Mike]

Re uPVC windows in particular, I posted here about why I avoid them: