ᐅ Which smart home system is best for retrofitting?

Pwnage619 schrieb:

What would bother me is if they run on batteries. It would be ideal, for example, with window contacts that operate on EnOcean (maintenance-free).

Punctuation helps.

Ideally, the window manufacturer should install the contacts directly into the windows. This way, they remain invisible. The electrician then connects them to the wired (bus) system. That would be the proper solution.

I found the Eltako FTKE window contacts via Google. They cost around 50€ each, but at least they are invisible when the window is closed. There is a picture of them installed on Amazon.

In this forum, mainly the basic topics are discussed (primarily house construction itself and dealing with the electrician/building partner). But that’s usually it, because there are other forums that focus more specifically on the respective smart home systems.

You’ve already got an idea of the direction to take. If possible, try to have the wiring installed in a "star topology."

I would also avoid using batteries. Currently, I have a Zigbee temperature sensor in every room. The batteries last surprisingly long. Still, it’s obviously annoying when you have to replace them. There are also switches with integrated sensors that can be retrofitted. You can’t really go wrong by installing these, even if no cables were laid initially. Even the Homematic IP motion detectors run on batteries, supposedly with a 2-year lifespan.

I didn’t expect that the windows could be connected via the bus system.

To be clear, if possible, wired smart home systems should always be preferred (with star topology wiring, you can connect any wired smart home system to it).

Wireless should only be considered if wiring is not an option due to cost or if you are not dealing with new construction.

I spoke with the builder, and he isn’t familiar with this either, but Busch free@home has already been installed before (there doesn’t seem to be a huge demand for it).

What do you think of Busch free@home? It is said to be an affordable and user-friendly alternative to KNX for private users.

Pwnage619 schrieb:

but very, very expensive (at least 10-15 thousand euros) and very difficult to install and program.
For changes, you often have to call an electrician (unless you have extremely good programming knowledge).

These are myths, mostly written by people who have no knowledge of home automation.

Pwnage619 schrieb:

What do you think of Busch free@home? It’s based on KNX and even uses the same cables.
It’s supposed to be cheaper and easier to program (so aimed at private users).

You already mentioned the disadvantages. Very basic functions and many limitations. The biggest advantage of KNX — manufacturer independence — is missing. It’s also not necessarily cheaper than KNX.

Pwnage619 schrieb:

We had imagined spending a maximum of 5,000 euros now on smart home (preferably less), but if cables need to be laid, you have to do it right away.

Exactly. If you want a smart home, you need cables—more than the standard installation from the general contractor provides—regardless of how it is controlled later. Even wireless sensors and actuators suddenly need power to switch.

Pwnage619 schrieb:

What options does KNX offer for window contacts that look good, maybe even invisible?

Choose from many. 99% of all variants can be connected to the bus, regardless of the manufacturer. Only if they use their own proprietary wireless protocol might there be difficulties, but even then a solution is often possible.

Almost all can be installed invisibly.

Pwnage619 schrieb:

What would bother me is if they run on batteries. Ideally, for example, window contacts running on EnOcean (maintenance-free).

There are only two battery-free options:
Wired
EnOcean

Pwnage619 schrieb:

Motion sensors were not planned initially, but could they be added later?

Motion/presence sensors are an essential part of lighting control in buildings. They can also be integrated into alarm systems and other automations, such as shading. Many functions only become “smart” when the system gets eyes and ears. Motion/presence sensors provide exactly that.

Retrofitting is possible, but often results in both visual and functional compromises.

Pwnage619 schrieb:

So, to sum up, whenever possible you should always prefer wired smart home (with star-shaped wiring, can you connect any wired smart home to it)?

Please free yourself from the idea that there is “smart home to buy” straight off the shelf or bargain bin. Smart home is not a physical product. It is always a combination of several systems in the building’s technical infrastructure.

There is no strictly wired smart home or wireless smart home. Rather, there are wireless and wired protocols that enable devices to communicate with each other.

Pwnage619 schrieb:

You should only rely on wireless if cables are not an option for cost reasons or if it’s not a new build.

Wireless isn’t necessarily cheaper either if you compare apples to apples.

Pwnage619 schrieb:

(there isn’t much demand for that, right)

No, there are too many disadvantages and it’s not really attractive price-wise. Only if someone doesn’t know better and wants to sell something to the homeowner is it a simple and easy system.

Pwnage619 schrieb:

How do you find Busch free@home? It’s supposed to be an affordable and user-friendly alternative to KNX for private users.

Supposedly, but it is not.

Pwnage619 schrieb:

I didn't expect the windows could be connected to the bus system.

They are not connected directly. Window contacts, such as reed switches, are installed in the window frames. You do not connect these directly to the bus but to a binary input instead. Only these inputs are connected to the bus system. This way, you can connect window contacts from any manufacturer A to a binary input of any KNX component manufacturer B, or to binary inputs of any bus system from manufacturer C.

Again: first define for yourself exactly which functions, comfort features, and aesthetics you really want, and how important all that is to you. I believe that with your budget of €5,000 (about $5,400) you won’t get very far. With that, you could have the essential cables installed (I don’t know what that really means for you), and then handle the rest with the retrofit solutions mentioned over the next few years.

Ok
I have seen that smart home systems are subsidized by KfW and BAFA.
Can I apply for this subsidy if the developer installs it for us?
Is this subsidy independent of the KfW 55 loan? (This has already been applied for)