Ok, well this is my essay on why, after many hours of research, I think it’s currently difficult to retrofit a UK home with Z-wave.
As I understand it, a resistive load is basically a conventional incandescent or halogen bulb. These are extremely energy-inefficient (although I do love the white light of halogen bulbs). I believe that a CFL bulb (ballast etc) would be a capacitive load - please note my knowledge of electrics is very sketchy!
Anyway, this is actually a huge problem for retrofitting home automation in the UK. It’s because all the wall switches in our houses are wired with just two wires - live flow and live return (probably the wrong terminology). This means that there is no neutral, and so a regular z-wave on/off switch (which would work fine with a capacitative CFL bulb) cannot be powered. The only answer is to have a dimmer switch, which somehow manages to draw power by putting the light on at a very low level (too little to be visible). The new Fibaro Micro Modules for example do this… and realistically I think they’re the best option for retrofitting… as you get to keep your existing light switches… cosmetically appealing and also avoids the problem of many switches being incompatible / badly fitting with UK pattress boxes.
However, all of these 'dimmer’s switches only work with resistive loads, and these are just not an option for most UK householders (waste of energy etc). I have even tried dimmable CFL bulbs (Varilight) but they didn’t work very well.
So, there is a further bodge which I looked into… you can use a switch module at the lamp itself - which can switch on and off properly as there is a neutral present at the lamp itself. Without dismantling ceilings etc, the most obvious solution is an in-line switch that goes between the fixing and the CFL bulbs, and this would be controlled by remote z-wave switches (e.g. battery powered units). However, there doesn’t seem to be any module that’s 240v and also a simple on/off switch (rather than a dimmer requiring a resistive load). Even if I could find such a thing (I haven’t yet), the chances of it being the UK standard bayonet fitting seems very slim (so you’d have to rewire all your light pendants to ES).
I would love to be proved wrong, but it’s looking like Z-wave in its current incarnation is just not suitable for retrofitting to UK wiring, unless:
- You’re building a new house / rewiring - not retrofit.
- You are happy using only incandescent / halogen bulbs everywhere (IMO extremely inefficient, and they don’t last as long either).
- Anyone can find a bayonet lamp module that’s 240V. If you’re prepared to change all your pendant fixtures then I guess ES could be used instead.
I’ve noticed that the proprietary system Lightwave RF, which appears to be designed for the UK market, have integrated the switches into the actual CFL bulbs themselves. Seems a terrible waste as presumably you have to throw away all the control electronics when the bulb blows, but I guess that’s the only neat retrofit solution for the UK given the way we wire our light switches. I’d prefer to use Z-wave with it’s proven flexibility, rather than this proprietary solution.