[Germany] building a new custom Home

Hey HomeAssistant Community,

I’d like to pick your brain on something. Yesterday my wife and I decided to take the first step towards building our custom house, by putting in a down payment for the soon-to-be building ground.

So now my head is spinning around with possible solutions for home-automation and what “needs” to part of the initial installation and electric wiring and what’s “nice to have”.

Other than the default CAT6 everywhere - Neutral wire everywhere and maybe a few strategically placed CAT6 and electricity outlets I’m quite indecisive when it comes to

“How do I want to manage my lighting”

Right now I’m thinking about running all my cables for switches, lights (and maybe outlets too?) to the utility room (in german we call this “Sternverkabelung”) to give me the ability to have a dumb house and put “smart” where it needs to be.

Then maybe some (a lot?) Shelly 1 (2 | 3) on a DIN rail within the utility box to control these things. <= Will WIFI interference kill me here? (~20 Shelly within a big utility box)

Do you have any other recommendations of things I should consider?

My Hub is a HomeAssistant instance with Deconz for Zigbee (should I add Z-Wave for the new home?)
I’m somewhat proficient in doing some ESP-based DIY solutions.
Unifi based network

My main goal is to not push my budget on “smart home” during the initial building of the house but rather give me the ability to put things in after the fact (I will order a little bit of extra space behind every switch and outlet so I can put stuff in there).
Everything should be “cloud service optional” and if there is a “somewhat” easy way of replacing a solution (e.g. Shelly <-> the next best thing) this is definitely a plus

Would love to get your opinions on this :wink:

If I had a chance for a wired setup, I would have used a bus system that can be extended without more wires to the central switch box.

However, I didn’t have that choice, so I use various systems now in parallel, mostly Homematic and Zigbee. Having constant stress with Homematic, I am going to replace more and more Homematic devices with Zigbee equivalents. I think in-house there’s no noteable difference between Zigbee and Z-Wave, at least if you choose the Zigbee / WLAN channels wisely.

Wouldn’t go for Wifi device, as there is no common protocol standard and Wifi addresses high-speed, high-volume networking on short distances.

What kind of Zigbee Devices are you using?

Hi Jonas, we started building a house 2 years ago and live in it one and a half years now. I have almost everything as “Sternverkabelung”, but I decided for using KNX for all “important” stuff (light, cover, room temp. control).
Almost all of the lights are 24V DC with KNX dimmers. So I have 8 DC power supplys in the utility room and 8 dimmers with 4 channels each. I have “5 core cables” (5-adrige) to each group of lights - so i can decide for 230V or DALI later. From each group of lights a cable goes to the utility room, to the dimmers.
Same for each cover.
And a KNX calble through the house for the presence detectors and the “push-buttons” (Taster).
So I have >>100 cables to the utility room, but I think I’m very flexible for the future. And KNX won’t stop soon, it’s already 30 years old and a lot of companies build devices for it.
But: it’s a decision you should make in advance. You can extend the system later, but you cannot “retrofit” the whole system later. And you have additional costs of several 1000€.
But it’s very reliable and stable. For me, it was the right decision.

1 Like

I would not use 20 shellys inside a single (metal) enclosure. Either an older raspi model with ethernet, a raspi zero with external usb ethernet adaptor or an esp with ethernet shield and then a multi relay module rated for mains. That would reduce the wifi devices to one or zero if you decide to do ethernet, what i would prefer. But i would also add a so called “Hotelschaltung” or “Wechselschaltung” to your lights: You can always overide the smartswitch when theres IT problems. You need an isolated between the light and neutral tho, to always get the correct light state. Its a bit more setup to do, but having no lights when the network or the server is down can be more frustrating.
A possible wired bus could be CAN, which is mostly used in cars, its more DIY, but it uses just a few wires for power and data and doesnt need to run a seperate cable for every device like ethernet. The german Youtuber BitBastelei made his own CAN bus devices, here are a few vids of it:



  1. Instance:
  • Coordinator device is “Slae’sh” CC2652RB USB stick
  • Philips Hue bulbs and LED stripes
  • ToYa (Blitzwolf) smart sockets
  • icasa “Unterputz” switch
  • CC2530 device with PTVO firmware.
  1. Instance:
  • Coordinator device is a Dresden Elektronik Raspbee II
  • OSRAM/LEDvance E27 bulbs
  • Innr E27 bulbs
  • Innr smart sockets
  • IKEA Trådfri E27 bulbs
  • IKEA Trådfri GU10 bulbs
  • IKEA Trådfri motion sensors (indoor)
  • Philips Hue motion sensors (outdoor)
  • CC2530 + CC2592 routing device using PTVO firmware

In both cases, coordinator software is Zigbee2MQTT standalone.

Right now I’m thinking about running all my cables for switches, lights (and maybe outlets too?) to the utility room (in german we call this “Sternverkabelung”) to give me the ability to have a dumb house and put “smart” where it needs to be.

We nearly did this in our renovation build but ultimately decided it was overkill. Also, the contractor was confused by the idea. They are used to doing things a certain way!

I then also considered running cat6 to every light switch and doing some kind of PoE or switching interface to home assistant to avoid wifi.

In the end I experimented enough with wifi and esp8266 boards and decided they were reliable enough to just build my own switches. They have a small mains ac to 5v buck converter stuck behind a regular switch. The live and neutral are then connected straight to the smart bulbs or shelly dimmer/switch.

The pro is if we ever were to sell the house it could be returned to regular consumer wiring over the course of a weekend.

Most of the house is either Shelly dimmers / switches or INNR brand zigbee bulbs through a conbee. I also built dimmer switches that look like regular mains dimmers - they operate through esphome and currently adjust brightness or after a long press adjust colour temperature.

Building new I would also always choose KNX (and maybe DALI for constant current LED dimmers) again. It’s not that expensive if you don’t fall into a automate-everything-hole but it can for sure be expanded to nearly everything.
And you can have professional help/support if you want/need. Don’t underestimate the amount of time doing everything yourself will cost.

1 Like

I second the voices to rely on KNX if you have the chance to build the cabling. I started my smart home journey in 2006. I fully put my bet on KNX in that time. KNX cabling and CAT6 basically everywhere. I did have ONE single failure of a KNX node which was a HW issue. All other devices run smooth for 15 years now.

Be aware, if standard things like lighting, covers, heating stop working you will have a WAF<<0. You don’t want that. Basic things need to work reliably.

And think of selling your property once in the future … I can not imagine buying a house which is relying on ZigBee or alike. You might find a nerd which loves it, but this limits your buyer base significantly.

For the basic stuff go for something which is reliable. All the fancy stuff can be Wi-Fi/Zigbee whatnot.

PS: I make my living in optimizing wireless networks, that’s why I rely on cables if I need reliability ,-).


Hey @tenn0 did you ever build an ESP based multi-relay module? Is there anything to look out for to make sure it’s “rated for mains”, or can I just buy something like (24V 16 channels)

Never built by myself, but the ones you postet are working with 5v on the trigger side and are rated for 250V 10A at the switched contact. For lights, that should be enough, but the washing mashing could get some trouble. But i wouldnt buy these on aliexpress, since between the switched contacts it can ark over wh en switching, which will weld the contacts together. Its safer do get relays from the home improvement store or ask your electrician which ones to get, he also has to install them. Seriously, dont mess with mains.



Then you don’t have to make the wiring decision.

I’m just searching for KNX. Seems an order of magnitude more expensive than zigbee/wifi. What devices do you buy?

Gira, MDT, ABB, Jung, Ekinex you name it… I’m running a mix.
It’s definitely not for upgrading some existing thing - especially rental. Wiring has to be done completely different - easier imho but more.

To get a rough picture: Price for the electrical installation of my whole house (only hardware, cables, conduit - I did installation myself) was roughly the same as for the kitchen (including installation and appliances).

I’m sure it can be done cheaper with similar capabilities. I just like it to be hard wired and as reliable as it is - hopefully for centuries.

1 Like

Gira/Abb are quite expensive. The market diversified a lot in recent years. Look for other brands eg MDT.



I also prefer wired. And I am building my house from scratch so I can do whatever i want. The problem is that I am either looking at things wrong, or KNX is +/-5 times more expensive than wireless solutions

They are very very nice!!.. still almost 100 euros for a switch :S

We have build our home in 2018-2019, living here since the end of 2019. I can vouch for KNX as well, it’s rock solid and provides a reliable base.
Like said before, for me it’s operating the basic things, mostly lighting and covers for now, but I’m expanding into power measurement and socket switching right now.

I agree that some of the hardware can be expensive, what we have done is the following: Since we are in Belgium, we have 2 ‘standard’ socket and switch manufacturers that basically everybody used, so we went with those as well (uniformity accross all visible wall plates etc). Behind these, I have hooked up some in wall MDT interfaces (https://www.mdt.de/EN_Universal_Interface.html#), these can be programmed to do whatever you like, single click, double click, long click. So these control my basics and they come in way cheaper than switches from KNX manufacturers themselves (ofc you’ll still need to count in the switches from the standard manufacturers but they are quite cheapish)

Another one for lights especially if you are looking for dimmable lights is the DALI standard. There is a KNX gateway and with this you can have cheaper prices per dim channel. Breakeven is probably at 3-5 dimmable channels comparing native KNX dimming vs the road via DALI.


Thank you very much for all your input. There is definetly a lot to think about. My local electrician (prob. not the one building the house) is heavily invested in Luxone. Does anyone here have experience with it(especially vs. KNX?)? There is a HACS Component available.