While we are focusing mostly on new-builds it is almost inevitable that you will get requests to do installations in existing homes/buildings.

One of the better options, IMHO, is to go wireless.  Have a look at http://www.zigbee.org/en/
 

The idea with zigbee is that it is low-cost, low-maintenance and also fairly easy to set-up.

Any ideas or opinions about this?

Cheers

AD 

Adriaan

ZigBee and Z-Wave are two emerging wireless standards that use the same 2.4Ghz spectrum as that of wireless Ethernet but have the benefit of requiring much less power at the client end of the circuit ( a light switch for example ). In addition they both  work using mesh networking topologies, ( each node relays messages from its surrounding neighbors ) . This results in a much more resilient and reliable low energy wireless network and the end nodes can rely on batteries or even in some cases generate enough power from the mechanical properties of the device ( push a button for example ) .. The vast majority of wireless based home automation product in development, across the board, is based on one of these two standards. ( Neither are perfect at present, security for example remains an issue that isn’t yet resolved to an acceptable level in our opinion )    

PLC (Powerline Ethernet) is Ethernet over power cable.. and another data contender for the retrofit market, again with some limitations

We (Andy and I) did some testing with some early zigbee and where not sure it was ready. The big plus for using zigbee is to enable cableless sitches but we found the response time for what are described as sleepy nodes was too long. A light switch needs to respond within 100mS or the user will push multiple times. Also was the issue of feedback to the user, mimics etc.
 

For some of the retrofit we would suggest the installing of webbricks within the control area, the room etc. So that most wiring is local and then a single backhaul cable to the central point.

I think the best use of wireless in retrofit at present is as the backhaul from each area of control. This all depends on how far the refurb is going. Is plaster coming off the walls? Can existing local cable be reused.

We are still looking at wireless connectivity.