When choosing uPVC windows, compare specific profile systems rather than brands. VEKA, Kömmerling, Salamander and Gealan are German profile makers, and each has simpler and more advanced systems. What counts is frame depth, the number of seals and the Uw value of the whole window. Below are the systems we sell side by side, and eight mistakes we see most often when people choose.
uPVC windows ranked by Uw value
The Uw value tells you how much heat is lost through the whole window, frame included. The lower, the better. The "Uw from" figures refer to a 1230 × 1480 mm reference window with triple glazing and a warm-edge spacer.
| System | Depth · seals | Glazing | Uw from | |---|---|---|---| | Salamander bluEvolution 92 | 92 mm · 3 | triple only | 0.71 | | Kömmerling 88 MD | 88 mm · 3 | triple only | 0.73 | | Gealan S 9000 | 82.5 mm · 3 | double or triple | 0.74 | | VEKA Softline 82 MD | 82 mm · 3 | double or triple | 0.75 | | Salamander bluEvolution 82 MD | 82 mm · 3 | double or triple | 0.75 | | Kömmerling 76 MD | 76 mm · 3 | double or triple | 0.77 | | VEKA 76 AD | 76 mm · 2 | double or triple | 0.81 | | VEKA 70 | 70 mm · 2 | double only | 1.32 |
The differences between the best systems are small. Double versus triple glazing and good fitting make a bigger difference. All 15 systems are listed under uPVC windows.
The most common mistakes when choosing
1. Comparing the glass instead of the window
Ug is for the glass, Uw for the whole window. A quote with a good Ug but no Uw tells you nothing about the frame. Always ask for the Uw. More on where the Uw value comes from.
2. Counting chambers instead of seals
Chamber counts look good in adverts, but at the same depth the third seal often matters more. An MD system has a centre seal that keeps out wind and driving rain better and dampens noise. On a busy road or an exposed site, you notice the difference.
3. Choosing a 70 mm profile
70 mm systems only take double glazing and have a Uw from 1.32. In Germany that is already too weak for a replacement window: the GEG requires no more than 1.3 W/(m²K) there. A 76 mm profile with triple glazing is well inside that.
4. Special glass in a system that can't take it
Safety, acoustic and solar control glass is available in systems with triple glazing. If you want laminated glass on the ground floor or acoustic glass facing the road, pick a triple-glazing system from the start. Which glass goes where is covered here.
5. Two narrow sashes instead of one
An opening sash must be at least 450 mm wide. In a narrow window, one sash plus a fixed pane works better, and costs less, because every sash adds hardware.
6. A colour that can't be made
In uPVC you get colour outside with white inside, or the same colour on both sides. We don't make two different colours or colour on the inside only. There is also one colour per order, so choose it for the whole house.
7. Roller shutter and fly screen added at the end
A top-mounted roller shutter has a box on the window that adds to its overall height. Deciding after the drawing is approved means a new drawing and a new quote. Fly screens can only go on opening sashes, not on fixed panes.
8. Comparing a fitted quote with a supply-only quote
A local company usually gives one price for windows and fitting. We sell the windows only, online, without installation, and transport is shown separately, per place on the rack by delivery country. To compare fairly, split product, transport and labour in both quotes.
Two mistakes we correct in quotes
We have worked with windows since 1997 and delivered more than 5000 orders. On every quote we check sizes, opening sides and descriptions. The two things we correct most often are the opening size given instead of the frame size, and an opening side described from outside. That's why every customer gets a drawing and specification to approve before production.
Comparing on your own project
The best comparison is with your own windows. In the window configurator you enter the windows once, then switch systems and see the price straight away, for example Kömmerling 76 MD next to VEKA Softline 82 MD. If you're torn between uPVC and aluminium, read uPVC or aluminium.