ᐅ Blind Control System for New Construction (Multiple Units per Switch Box)

Let’s just say, I’m probably the biggest beginner in our family! )

Personally, I prefer classic light switches (push buttons) for simple on and off control. But I also understand dimming, like with an electronic dimmer.
I find dividing control areas across a switch panel useful, for example with roller shutter control, since it saves space on switch slots, or for switched sockets.

Combining ring wiring and radial wiring seems possible based on what I’ve read so far, right!?
I’m thinking, for instance, that in ground floor wiring the ring is laid in one main direction, but a sensor unit on the opposite side still needs to be connected.

When does a KNX line need to be run to a load? Like for venetian blinds/roller blinds, lights, sockets?

So many questions!

Good luck,
Thomas

molchi schrieb:
When does a KNX cable need to be installed to a load?

Never. Because it is a data cable.

The KNX cable only needs to be installed at every location where a KNX device is or will be.

In the minimal setup, it looks roughly like this:

from the distribution board (where the actuators, power supply, and interfaces are located) to the switch/button (called sensor in KNX terminology)

End of story...

Of course, this is not necessarily how you would usually do it, but it would work.

Another advantage of KNX, especially when no cables are installed yet, is that you can configure it however you like. At the entrance to the living room, a standard push button (with KNX built-in) to control lights on/off/dimming and (if needed) two groups.

And at the patio door, on the sofa, or anywhere else, touch sensors with any number of functions for lighting, roller blinds, air conditioning, heating, weather forecast, alarm messages, temperature display, and so on.

In this scenario, a standard cable (like cable type NYM) at the light switch would be the fifth wheel on the wagon—completely unnecessary.

Of course, this assumes everything in this room/area is controlled via KNX.

The other rooms can still be wired conventionally.

Here is a picture to illustrate the system:

And here is a very, very simple comparison boiled down to a two-way switch, conventional vs. KNX.

I recommend creating a plan for the entire house: decide where you want certain features such as dimmable/colored lighting, blinds control, visualization, switches, presence/motion detectors, window contacts, etc. And not based on "what can I currently afford?" but really on "what would I want if I had won the lottery?"

Accordingly, the basic installation, meaning the wiring, should be done upfront.
The additional effort compared to a conventional installation is actually quite limited, especially if you have technical skills and can do a lot yourself.

After that, you can consider gradually expanding the functions.

Starting with a 20-channel switching actuator for the lighting throughout the house. Possibly a 4- or 8-channel dimmer, two blinds actuators, and you have the basic functionality covered for around €2,500 (including power supply and interface).
ETS5 lite is sufficient for this, and configuring these functions is quite straightforward.

If there is leftover budget, you can add presence/motion detectors, group lighting circuits into scenes, implement blinds automation (with weather station), realize a night mode, and much more...

Imagine you equip only two or three rooms with KNX and then (and I am quite certain you will) want to dim the lights in a fourth room or implement a “central OFF” function at the front door.
That won’t be possible.

Therefore:
install all fixed wiring components fully and comprehensively from the start—everything that is built-in and either cannot be changed later or can only be changed with great effort—
and implement everything that can be easily retrofitted only when it’s possible and/or desired.

Hey!

I think it keeps getting better!

Is it really worth installing window sensors if you don’t do it right away?
They’re mainly for intrusion detection and window open status, right?
Do the blinds motors not require KNX wiring? They have limit switches installed, and if the venetian blinds need to be properly aligned...

While reading more, I came across the company Hager and their KNX-easy product.
Unfortunately, the information on their website is quite limited.
Does anyone know what the advantages are?
The system is said to be compatible with the ‘standard’ KNX.

Have a great weekend, everyone!!

Hello,

usually only 5x1.5 cables go to the roller blinds; the actuator is installed in the distribution box, and the rest is configured in the ETS software. Optionally, you could also run a green KNX cable to each outlet to check the window contacts directly at the outlet.

BUT each window contact costs you between 50 and 100€ from the window manufacturer, and each KNX bus actuator costs about 40€ more.

This is one of the reasons why people often say KNX is SO expensive. Suddenly, expectations rise, and all of this costs EXTRA. People simply don’t talk about these things when dealing with standard electrical installations.

Hager EASY is an attempt to sell KNX light to people. Personally, I consider it a way to dumb people down. B&J does this perfectly. They sell their Free@Home system as THE solution, but it’s not even cheaper and is actually more limited in functionality compared to the ‘same’ components in KNX.... But people just want to be fooled! It’s like putting a “SPECIAL OFFER” sign in a supermarket — people buy it. Most of those who bought it only realize later how limited they are. This is especially true for sensors. For KNX, you get pushbuttons starting at around 60€, or even from 40€ if you use a bus actuator in the wall combined with a classic switch. In B&J’s Free@Home, they basically do the same as the actuator solution in KNX, but they sell it as a switch, for example, a single switch for 35€, a double for 45€, and so on. The actuators cost MORE than with KNX, and once you have Free@Home, you’re locked in. With KNX, you can get devices from any manufacturer you like, and everything works!

There have also been many improvements in KNX programming recently. Now there is ETS Inside, which costs 160€ and is limited to programming only one line and up to 255 devices. But that’s more than enough for a single-family house. And you’re not limited in your choice of devices. So I can only recommend KNX for home automation.

Just my 2 cents.

molchi schrieb:
Don’t the roller shutter motors require a KNX cable connection? There are limit switches installed there, and if the venetian blinds need to be properly aligned...

It depends on what you install. For motors with direct KNX connection – yes. For others – no.

As Tom already mentioned, window contacts get expensive, but that’s mainly because with conventional setups they aren’t installed at all. So this item is missing for the average homeowner, and that’s when the debate starts: KNX is luxury, overpriced, and so on.

However, it’s important to compare apples to apples and pears to pears.

With KNX, your appetite grows while you’re eating, so the system tends to expand more and more over time.

BUT: You don’t have to install everything right away. You just need a plan for where, how, and why everything should be controlled later—and initially (for what feels like the hundredth time, here’s the tip) run KNX cables everywhere!

Additional cost: maybe around 100 euros (about 110 US dollars).
Flexibility and expandability afterward: priceless.

Whether to install window contacts or not is up to you.

I use mine for alarm systems, shutter control, status indication, and lighting control. Two contacts per sash cost me an extra 50 euros (about 55 US dollars) including KNX integration. But as I said, it’s not mandatory. In a minimal setup, however, I would definitely install some on frequently used doors.