ᐅ Window quotes as different as day and night

@dertill
No, not between Polish and German, but between plastic triple-glazed and plastic triple-glazed. The place of manufacture doesn’t matter. In the end, the brand Müller comes from the same production line as Woski.
According to the window manufacturer, there are such low-quality triple-glazed units that it would be better to use higher-quality double-glazed units instead. It just takes advantage of the common belief that triple glazing is always better.

dertill schrieb:
We used these during our renovation of a single-family house as well. 50m² (540 ft²) of window area, including the front door, triple-glazed with warm edge spacers and colored film. The gross price was 9,000 (including installation) for Drutex, around 12,000 gross would have been the price with profiles from a German manufacturer (the name escapes me at the moment). There is nothing to criticize about the windows.

What’s the difference between the “German” and “Polish” products? Drutex uses hardware from Mako – which you’ll find with about 50% of German manufacturers as well. U-values are the same everywhere; Drutex offers from passive house windows with a Uw of 0.7 (including front door) to standard ones around 1.2, just like most others.

@kaho674 Calculated from our 50m² (540 ft²) area (including front door with Uw 1.0), we paid about €270 (approximately $290) per m² ($24 per ft²) window area with the film – installation included! Without the film, it would have been approximately €250 ($270) per m² ($23 per ft²). Based on your 20 windows / 38m² (410 ft²), that would be about €9,600 ($10,300). That seems reasonable. However, €35,000 ($37,600) sounds like a lot – our highest quote was €400 ($430) per m² (all without plastering work).

BUT: The installation crew we had was a complete disaster, and in the end, I didn’t pay for everything and fixed the defects myself. Be sure to insist on proper installation and ideally demand a written confirmation of RAL-compliant mounting. Ask how it will be implemented and make sure to check!

Please add some details about what was so disastrous. We are currently installing windows and I'd be interested to know if I might have overlooked something. Thanks.

dertill schrieb:


BUT: The installers we had were a complete disaster, and in the end, I didn’t pay in full and fixed the defects myself.
Make sure to insist on a proper installation, preferably requesting a written confirmation that it complies with RAL standards. Ask how this will be implemented and check carefully!

I’m less worried about that. The installer has already built and installed several things for acquaintances, and everyone is very satisfied.

Zaba12 schrieb:
We are currently installing windows... I would be interested to know if I missed anything. Thanks

What method did you use? There are several options for RAL-compliant installation (triple-compression tape, sealing tapes, plaster sealing profiles).

What didn’t work for us, for example:
- Support blocks either completely forgotten or just cut from a random roofing batten (spruce/pine)
- Fixing not done continuously around the frame
- Wrong compression tape used (2–4 mm on joints of 5–15 mm) — fills the gap but is not resistant to driving rain
- Wedges "forgotten" and only removed afterwards (now foam is missing)
- Surface under sealing tape not cleaned or primed (tape won’t stick)
- Fixing tabs not fully covered with sealing tape (leakage in the resulting "hole" next to the tab)
- Initially planned to omit sealing tape at the bottom ("the windowsill will cover it")
- Sealing tape not properly bonded at the corners, with obvious holes later half-heartedly patched
- Exterior sealing tape at the bottom not correctly overlapped and partly not installed as a "drip edge" or "tray"
- Sometimes wrong screws/anchors used (Poroton bricks have different requirements than, for example, sand-lime bricks)
- Sealing tape sometimes installed without an expansion loop
- Used sealing tape for plastering on the wooden dormer
- Compression tape sometimes not fixed properly and later bulged out

kaho674 schrieb:
The installer has already built and installed several things for acquaintances, and everyone is very satisfied

How many of these acquaintances had an expert present and/or have sufficient knowledge themselves? For most people, it’s enough that the window is aligned properly, nothing was damaged, and it doesn’t let air in with the slightest breeze – everything else usually goes unnoticed at first. I’ve definitely been enlightened on this!

Dr Hix schrieb:
What was used in your case? There are various options for RAL-compliant installation (triple-compression tape, sealing tapes, plaster sealing profiles).

What didn’t work for us, for example:
- Support blocks either completely forgotten or just cut from a random roofing batten (spruce/pine)
- Fastening not done continuously around the perimeter
- Wrong compression tape used (2-4mm for joints of 5-15mm) → fills the gap but is not resistant to driving rain
- Wedges “forgotten” and removed later (foam is missing there now)
- Surface under sealing tape not cleaned/primed (tape doesn’t adhere)
- Fastening tabs not fully covered with sealing tape (leak at resulting “hole” next to the tab)
- They initially wanted to leave out sealing tape at the bottom (“The window sill will cover it anyway”)
- Sealing tape not properly glued at the corners, with obvious holes later half-heartedly patched
- Sealing tape on the outside at the bottom not correctly overlapped and not shaped as a “tray” in some areas
- Sometimes wrong screws/dowels used (Poroton has different requirements than, for example, sand-lime brick)
- Sealing tape sometimes installed without a movement loop
- For the wooden dormer, sealing tape was used for plaster embedding
- Compression tape partly not fixed and later bulged out

This is how it is written in the offer and how it was also installed.