I am replacing my windows with double glazing lowE. Can report back on the workmanship in a month or so. Scouted for many companies, used the recommendations from the forum and got in touch with most of them.

Some gave poor consultation or simply have no idea on the glass specs they push on me, some dont even know the difference between U-value and UV-transmission, some cannot respond to inquiries at all or communicate with their staff. This was my experience with the larger providers for alluminium and uPVC windows. Some of the frames offered were very very convincing but if the company has very very limited knowledge about what sort of glass they put inside that frame this is of little use.

I also found companies with great glass but rather unsuitable frames with super old style locking mechanism.

I the end found an in between solution where I placed more importance on the glass than the frame as this was most important to me.

If installation etc. is good I will place a recommendation here.

I dont think my costing will be of any use to you. It depends on the glass specification and I possibly went a bit overboard with what is essentially tripple glass with lowE but without any opening mechanism.

If you make the windows openable the cost increases, if you go for highend glass its the same. Then the size(s) of the window in question will also matter.

One fixed window for my setup with a size of 94" x 34" is around 3,150.00


If the installation and workmanship of the company is good I dont mind sharing. For now that is unknown.

Feedback on my glass configuration: 4mmTempered + 4 PVB + 4mm Tempered LowE + 12 Airgap + 4mm Tempered works very very well. Glass barely gets warmer than ambient. Direct sunlight around 38°C top temperature.

Installation and frame were soso. If you can tahan a standard installation then its fine. I would have expected more but well. I assumed this would be the case. Frame margin or error is sometimes visible, workmanship is OK but not great. If anyone wants I can share contractor. Cannot give an unreserved recommendation if you want to retrofit.