Not cheap, but I’ve been happy so far with UPB (Universal Powerline Bus) devices. They’re available as plug-in modules or in hard-wired versions. A little bit laggy on latency – they communicate at 4800 baud over the house wiring, with a 100 to 150ms delay before a UPB device responds to any command – but so far very reliable. More details about my UPB setup & experiences here.
On costs – for the USA & Europe I think the high per-unit cost of powerline home automation devices is a combination of 2 main factors:
- Low market penetration (home automation has been a luxury item / niche market until very recently.)
- Costs for safety certifications, e.g. UL listing, etc.
The actual manufacturing cost of the devices – after they are fully designed, tested, and approved – is probably a small percentage of the retail price, but the low market share means the retail price has to be high to amortize the upfront hardware development, certification costs, and ongoing marketing / distribution / support costs.
To some extent all consumer electronics are subject to this cost structure but when you’re manufacturing & selling 100 million GFCI outlets or 5 million electric hot water kettles, economies of scale often permit lower unit cost.
Perhaps the biggest barrier to broad adoption & subsequently lower cost for permanently-wired line-voltage home automation switches is the fact that 99% of electrical work is done by professional electricians, usually at the time of construction. I think there will have to come a tipping point at which HA-enabled line-voltage hard-wired switches become a common option in new construction – the way GFCI’s are now, for example. Not holding my breath for that to happen; most improvements to the default electrical design of residences is driven by safety considerations balanced against keeping the costs as low as possible.
There’s also the reliability factor — building electrical infrastructure is expected to be 99.999% reliable. Looked at from the installer’s perspective, why complicate a simple, cheap toggle light switch by putting a $50-$80 “smart” switch in that is far more likely to burn out due to surges or component aging?