Smart home consultation new construction wireless

So roughly estimated, KNX probably costs around 10k euros and, for example, a Homematic system 2000 €.
Then the manufacturer can go bankrupt 5 times before the KNX is worth it.
So I only see the advantage of interchangeability to a limited extent here.

Even if a manufacturer goes bankrupt, ... as long as you use a platform like Openhab, iobroker, etc., you can completely disregard that (the existing actuators continue to run...). The flexibility is unlimited; if a manufacturer goes bankrupt, I just buy actuators from another one. I can simply combine whatever I want. You can call it a makeshift solution or a maximally flexible system.
In my opinion, wiring only makes everything more complicated with less flexibility, without significant advantages in the single-family house sector (in commercial properties it is of course different, where there are thousands of actuators, possible failures can become really expensive, ...). Radio, WLAN do not even come close to their limits in a normal single-family house, and if a signal fails to get through every six months or so... well then you just click again...

Specific cost breakdown ... (example in my house):
~100 € PI, software free
Actuators (exclusively Z-Wave): 17*45€ blinds = 765€, garden irrigation: 2 * 45€ = 90€, awning 1x45€, lighting (only those I currently need): ~12*45 = 540€
Total: ~1,550€

Expandable at any time without having to have pulled cables everywhere in advance for all eventualities. And I won’t cover all eventualities anyway, because, as the past clearly shows, new applications always emerge that you can’t even anticipate now.
No extensive planning needed in advance, since at any time you can decide what you want and what you don’t. The only thing that takes a bit of time, depending on IT affinity, is getting familiar with the software. Without any IT affinity, it might not be entirely trivial.

Concrete cost breakdown ... (example in my house): ~100 € PI, software free Actuators (exclusively Z-Z-Wave): 17*45€ blinds = 765€, garden irrigation: 2 * 45€ = 90€, awning 1x45€, lights (only those I currently need): ~12*45 = 540€ Total: ~1,550€

I fully agree with you - and I have now also made a cost overview. I come to 1657 €, excluding hardware that I would have needed anyway (mowing robot, vacuum robot, TV). Price drivers are the 11 roller shutter actuators and the cameras, together 850 €. In addition, there may be 100 € of wasted expenses on things that did not work. When I consider that I paid 800 € just to the electrician for laying 5-core instead of 3-core cables everywhere and for an unwired EIB line, it remains a bargain. For that, I have the following functions: - 11 automatic roller shutters, also manually controllable - electricity consumption meter readable - gas meter readable (currently unfortunately only per m^3) - vacuum cleaner controllable via Google Assistant / room assignment via voice / vacuuming as soon as no one is there - mowing robot administrable via WLAN - lighting via motion detectors in 2 hallways + 1 room + outside, total 8 units - garden irrigation automated with power measurement for too long running, 4 valves - alarm system with 16 window contacts, including fence, motion detector outside - notification if window open when leaving - 4x cameras + RaspberryServer, triggered via PIR or motion detection - 1x CO2 sensor (room air monitoring to possibly optimize controlled residential ventilation) - 1x brightness sensor (for light setting / roller shutter) - 3x smoke detectors, roller shutters up + notification on phone + siren - notification on phone when children’s window opened - 1 water damage sensor under dishwasher - 4x outdoor lights switch on with motion - 3x Christmas lights on/off - ambient lighting living room/home office - access to controlled residential ventilation - access to fuel prices at my preferred gas stations, evaluation of when cheapest - access to TV - access to weather forecast (except current precipitation) - 1x rain sensor - temperature and humidity in 3 rooms - various Sonoffs controlling e-bike charging, 3D printer Planned are still access to the gas boiler and water consumption display. This year, only the CO sensor and 1 motion detector have been added, the rest just runs. Of course, you have to restart the Raspberry Pi sometimes. I have also cloned the SD card for small rule adjustments. If something happens to the Raspberry Pi, I wait 3 days, then a new one is there. Manually, everything still works. I doubt that KNX will come into this price range. And for that, it can also be a DIY solution that’s fun.

I am currently dealing with Z Z-Wave. Which actuators (manufacturers) do you use for dimming function and Venetian blind control?

I have looked at the Shelly ones, which are based on WLAN. They are top in terms of functions (except for slat control). But I don't like WLAN as a medium.

KNX was not a cost-effective solution for us.

I have so far used almost exclusively Fibaro. No failures after 3 years, integration has always worked quickly. Our neighbors also use it, likewise no problems.

I am currently dealing with Z Z-Wave. Which actuators (manufacturers) are used by you for dimming function and venetian blind control? I looked at the Shelly devices, which are, however, based on WLAN. Their functions are top (except for lamella control). But I do not like WLAN as a medium. KNX was not a cost-effective solution for us.

Hello! My whole house is basically controlled with Z-Z-Wave. As dimmers, I can exclusively recommend those from Qubino, much better than the Fibaro parts; I have them as DIN dimmers directly on the mounting rail and partly as dimmers in the wall boxes. The biggest advantage of these dimmers is that they can dim cleanly and flicker-free from as low as 1W power. The other dimmers cannot do this without a bypass. For the venetian blinds, I have the Fibaros installed. Overall, well over 100 actuators and sensors from various manufacturers are installed with us. Everything runs smoothly.....

That sounds good. Already reassuring.

One small question please.
Do you also have a wind/weather sensor in use? I would also be interested in the manufacturer and how reliable it is.