I'd just like to add a few things about KNX here. I have installed it in my new house (though not yet integrated it with LinuxMCE - I haven''t installed LinuxMCE yet....). Knx is very nice indeed, and quite industrial in its approach and construction.
Many manufacturers, and many vendors for it. I recommend knxshop
in the UK (who also offer training, which I went on and it gave me the confidence to install). You'll find you get a substantial discount on list prices if you open an account - but prices are cheaper in Germany if that is equally convenient.
I wired each electrical socket and light fitting (or group of light fittings in the case of spotlights) individually back to the electrical cabinet. I wired these to terminal block, supplied neutral and earth from consumer unit (in appropriately grouped sets) via power distribution terminal blocks, with live supplied from power distribution blocks via load relays (16A output). These were either wired individually or in groups of sockets - allowing me to switch them individually or in defined groups (for example all the kitchen ones were individually wired so that appliances could be switched on or off remotely, whereas in the lounge most sockets were grouped together, with two separate for lamps - so that lighting scenes can be controlled). With all the relays grouped together in the electrical cabinet I only had to run individual power cables. Then I ran bus cable (no mains power) to each switch location in the rooms (this cable can be run in a tree and branch topology so it's easy to wire from one socket to the next).
The switches that I used
also have thermostats, timers, and a set of inputs (allowing things like PIR's to be read locally). I also ran bus cable to each radiator valve
, to allow the KNX system to turn on and off the room heating (you can do the same with whatever heating or cooling you use, as long as you purchase carefully).
For each light, or group, I used these budget 4 output, 6 input
units (I used the inputs for things like PIR's, door contacts, and simple push to make buttons for door bells etc....).
In addition to the inputs, outputs, and switches, you need a power supply
and a bus interface
(I have a USB and also an IP one, but I've only used the USB so far for programming purposes - the intention is to use the IP one for LinuxMCE).
I chose to use KNX cable, but you could equally use cat5 or cat 6 (and have between two and three pairs free, possibly for wiring inputs).
You also need the software to program the devices (which is circa £1000 UKPounds). Don't go for the KNX lite offering, go for the full blown KNX. It's not cheap, but it really is very good.