What are the technical differences between Z-Wave and its Plus alternative? Is Plus just a stronger signal?
The Z-Wave Alliance have a page explaining the differences pretty nicely:
Z-Wave Plus™ is a new certification program designed to help consumers identify products that take advantage of the recently introduced 'Next Gen' Z-Wave hardware platform, also know as 500 Series or 5th Generation Z-Wave. [...]
With the introduction of the Next-Gen, Z-Wave 500 series hardware platforms, Z-Wave saw its ecosystem bolstered with new capabilities, including increased range, extended battery life, Over The Air upgrading (OTA), additional RF channels and more — all of which are fully backwards compatible with existing Z-Wave products. [...]
- 50% improvement in battery life
- 67% improvement in range
- 250% more bandwidth
- Three RF channels for improved noise immunity and higher bandwidth
- New Plug-n-Play Network-wide Inclusion feature
- Improved self-healing and fault tolerance with Explorer Frame feature
- Standardized method for Over the Air firmware updates (OTA)
- Improved product information capture for product certification database
Some miscellaneous differences are noted in a TechHive report:
The new chips also boast dramatically smaller packages. Sigma’s SD3502, for instance, is a general-purpose Z-Wave system-on-a-chip that integrates a microcontroller, RF transceiver, 128-bit AES security engine, and memory in a package that measures just 7mm square.
From the perspective of a consumer, Z-Wave Plus' main benefits are battery life and range. Many hubs (e.g. SmartThings) already support Z-Wave Plus, and many sensors and other nodes support it too. The Z-Wave Alliance claim that Z-Wave Plus devices generally won't cost a lot more, either, so in that case, it's probably beneficial to pick Z-Wave Plus if possible.
As a developer, the OTA updates and smaller chip are likely to be useful. I can't say much about the technical details, because the specifications are secured and require the signature of a non-disclosure agreement. If anyone has any additional information, I'd be interested to hear.