Which control system? Control heating/ventilation/air conditioning with an app

Hello,

when it comes to home automation, you cannot get past KNX. And sorry 11ant, PLC is certainly more than unsuitable for home automation. You can use it additionally in the distribution box for certain purposes (I do that with a Wago 750 as well) but already all the sensors (PM, BW, buttons, etc.) are a nightmare with PLC. Especially if you want feedback or information, nothing beats KNX.

Regarding the wiring, however, I agree with you. Everything star-shaped with 5x1.5 or 5x2.5 to the distribution offers maximum flexibility.

Which system would you recommend?

I'll try with a less dogmatic and polemical answer:

If future-proofing is important to you in the sense that a variety of manufacturers exist who will offer you compatible components even after a competitor disappears, I would go for a standardized system like, for example, KNX. In addition, you have a wide range of devices and can choose from a large selection.

If that's not so important to you and you don't mind dependency on one manufacturer, there are also other options. Loxone is often mentioned as an example here.

That these options per se would be just gimmicks or more error-prone and thus require more maintenance belongs to the realm of myths, but that doesn't really surprise coming from the mouth of a KNX enthusiast for whom the line sometimes blurs into fanboy territory...

A properly planned and implemented Loxone system tailored to the user will fulfill its purpose just as well and function properly. Period.

A poorly planned KNX system will just as much miss the users' needs and represent a money pit. Again, period.

The differences lie in the technical infrastructure, dependency on the provider, and handling of the product portfolio. I would consider that but would not let anyone convince me that there is only one option and everything else is nonsense.

Two things are said about Loxone: simpler parameterization and a cheaper installation compared to KNX.

Regarding point 1) I can't say much, regarding point 2) I can at least say in my case that an equivalent KNX system was by no means more expensive; through Loxone there was no price advantage, rather a slight price disadvantage.

I chose KNX because of the larger product variety and independence from one company.

Hello,

when it comes to home automation, nothing beats KNX. And sorry 11ant, PLC is definitely more than unsuitable for home automation. You can use it additionally in the distribution board for certain purposes (I do that with a Wago 750 as well) but just the entire sensor technology (PM, BW, switches, etc.) is a nightmare with PLC. Especially if you want feedback or information, nothing goes over KNX.

Regarding the wiring, I agree with you. Everything star-shaped with 5x1.5 or 5x2.5 to the distribution offers maximum flexibility.

So I do everything with a Wago 750 889. This controller can do KNX but I have no KNX actuators or sensors installed.

As switches, I have 8-gang switches with feedback LEDs, which means per switch panel I have 18 conductors + 2 conductors for the PT100 to measure temperature. So I laid 20x 0.5mm² for each switch.

The visualization is then done with Openhab. The heating completely via my Wago with its own control. The door stations and cameras are all integrated into the visualization via a Flash element. Lighting partly via Philips Hue because of the Ambilight for the TV, the rest via RGB dimmers directly on the Wago. Weather station and heating temperatures all via Wago.

With this, I’m easily half the price of KNX and more flexible because the Wago can handle almost all protocols or can be integrated.

When I read here that I need 20 cores, for me the fun stops there. If I have to connect cores for an hour at each socket and then do it all again in the control cabinet, no one will pay me for that anymore.

You can do that if you do it yourself, but not if you hire an electrician for it.

As I said, this is just my opinion and no, I don't see myself as a fanboy, I earn my living with such things. Actually, I should join the chorus of many other electricians and say KNX is 300% more expensive than standard. Then I would earn more money....

For me personally, I see that with a KNX system I have much less effort during installation (purely regarding drilling/grooving etc.) so that I have to spend less time on these things. You do stand longer in front of the cabinet, need a bigger one etc. BUT working in a cabinet is much more pleasant than breaking your fingers in a socket when you have to hook together X cores.

And as soon as the customer wants something beyond the normal standard, that puts a smile on my face. How often does it happen that the customer suddenly remembers during the implementation

'Uh, I would also like to have the light/shutter/socket ... controlled from here'

For me, that means relaxed 'No problem, we'll do it.' And everyone who has built a house knows that. I just had that case recently, the plasterer was already done and the builder wanted a few changes after all. Except for a 150 cm long groove and a flush-mounted box for an EIB cable and a pure re-termination in the cabinet, it was easy.

Classically, that would have meant half a dismantling of the electrical installation. That wouldn't have been affordable and the builder would have been annoyed again and again. So it cost him about 200€ in labor + material.

And that would not have worked that way with PLC either. But since KNX does not place high demands on topology, that is usually no problem.

These are all advantages that the customer 'normally' doesn't even consider.

Therefore, my recommendation is KNX and EVERYTHING star-shaped in the distributor. And above all, EVERY tiny wish should be mentioned in the planning. That way you can decide if it makes sense to possibly lay preparations in the form of bus cables in flush-mounted boxes as a reserve.

As always in life, everyone can now consider what is right for them and then implement (or have it implemented).

Hi ,
no worries, you weren’t meant with fanboy. A question for the pro regarding the star-shaped distribution. Suppose you have a triple socket on the left and right side of a wall. Do you then wire each socket with a 5x2.5 or 5x1.5 cable each to basically be able to switch each individual socket, or just one 5x2.5 cable total for both triple sockets together to have one constant power and two switchable channels?
My impression is that the latter is often done to keep the number of cables low, because quite a few cables add up that potentially have to be laid somewhere. If in the raw ceiling, collisions with ventilation planning can occur (very likely), if you lay them on the raw floor slab, they can collide with the sanitary installation and/or require a more expensive screed/liquid insulation. What are your experiences here? Reduce cables rather (as described above)? Cables in the raw ceiling or on the raw floor slab? How do you solve the insulation when some cable ducts run parallel (especially in the corridors)? Cheaper insulation boards are then ruled out, aren’t they?

Hi ,
Assuming you have a triple socket on the left and right of a wall. Do you then wire each socket with a 5x2.5 or 5x1.5 cable in order to basically be able to switch each individual socket, or just use one 5x2.5 cable for both triple sockets together, to have one constantly powered line and two switchable channels?

Well, I am a fan of a complete star wiring. 2.5 is only necessary for cable lengths > approx. 15m and protection with 16A (or for larger consumers like an oven). This is related to the tripping of the fuses.

Hi ,
My impression is that the latter is often done to keep the number of cables low, because quite a few cables add up that potentially have to be routed somewhere.

True, the amount of work is about the same since you have to make the chase accordingly and making horizontal chases is not so easy these days because it’s no longer allowed with some bricks. It’s easier to make a vertical chase, that’s why everything is centralized.
The additional cost for the cable is not that high. Then there are the terminal blocks in the distribution box and the wiring. In return, you save the horizontal chases, fiddling inside the socket and the ‘thinking’.
I also only use 5-core cables and usually wire them so that with a triple socket each phase conductor feeds one socket, simply bridged in the distribution box. For a 4-gang socket, the first two get one phase each and terminals 3 and 4 each get their own phase conductor again. And for a 5-gang, the first two sockets get one phase conductor, the next two sockets get another phase conductor, and the fifth socket has its own phase conductor. The advantage of this is that if you later want to switch a socket, you simply rewire in the distribution box. And you know: 1st socket black, 2nd socket gray, 3rd socket brown. And basically this for every socket.
This way you can turn a ‘normal’ constantly powered socket into a switched one without much effort in 5 minutes. (Happens more often than you think when it’s possible)

Hi ,
If installed on the raw ceiling, there can be collisions with ventilation planning (very likely)

Well, in my current project (approx. 640 sqm living space on 2 floors), about 200 cables run to the ground floor distribution box. Additionally, 22 ventilation pipes with 70mm diameter run on the ground floor. The only critical area is actually above the distribution box where several come together. But if it’s planned accordingly, it’s not a problem. In a classic single-family house, this is uncritical.

Hi ,
if you lay them on the raw floor, they can collide with the sanitary installation and/or require a more expensive screed/liquid insulation. What are your experiences here? Reduce cables (as described above)? Cables in the raw ceiling or on the raw floor? How do you solve the insulation if there are several cable ducts running parallel (especially in corridors)? Cheaper insulation boards are then mostly excluded, right?

Well, I try to avoid pipes on the raw floor if possible. Of course, it’s not always possible because planning and implementation are always two different things, especially if the clients are dynamic and keep coming up with new ideas or if a pipe is crushed during concreting so that no cable can be pulled through anymore. If there are more cables, the insulation is done in two layers so that everything can be accommodated without much effort. In really large projects (like my current one) it’s usually so that the clients do not want a standard setup, so the floor structure is designed stronger to allow for 10 cm impact sound insulation. You can fit quite a lot in there.

Hi ,
How do you solve the insulation if there are several cable ducts running parallel (especially in corridors)? Cheaper insulation boards are then mostly excluded, right?

As I said, best to plan properly and integrate it into the ceiling. Another option, and this can already be considered in the planning, is to lay one more brick and suspend the ceiling. With 10 cm suspension height, you can easily accommodate ventilation and electrical installations.
That is then the optimum. But you must keep an eye on the additional costs. However, if you want to use a lot of spots and LEDs, this extra effort may be justified because then you save the sockets in the concrete ceiling.
Ultimately, it depends again on personal preference how you want to do things. If money is no object (it exists), then 3m rough construction height, 20 cm floor construction and 15 cm suspension.
Ultimately, the wallet and personal taste decide how you do things. Visit 5 construction sites and you'll see 5 solutions.