Both Zigbee and Z-Wave operate through a mesh network. Zigbee travels on a higher frequency (2.4 GHz) versus Z-Wave (900 MHz). Zigbee waves travel further, albeit on a more crowded frequency. Both networks are mesh network protocols, meaning that modules/nodes relay signals, as well as receiving and responding. In essence, the more modules throughout your house, the more distance your network can travel.
Z-Wave allows for up to 232 nodes, while Zigbee allows over 65,000 modules on its network. Zigbee also seems to be making more headway with appliance makers and, given its ability to travel further with more devices, is more apt for commercial projects. The 2.4 GHz frequency also give Zigbee more bandwidth, meaning it can carry more information like Meta tags, through it’s network. Oh, and to top it off, Zigbee is open source, which I generally support.
All-in-all it sounds like Zigbee is better, right? I think on it’s face, Zigbee is better, especially for large applications. For my home, Z-Wave is the right choice. The strengths of Zigbee are ultimately the weaknesses of the protocol. Confused?
Zigbee can control more types of devices with it’s larger bandwidth, but that also means there’s more code in the Zigbee protocol and ultimately more difficulty with cross-compatibility. Think of it as Windows vs. the Mac OS’s. Whereas Windows kept adding and adding support until the OS was enormous and slow. Mac would clean out its support with each new OS, creating a smaller, more consistent product. Z-Wave is more like Mac in this sense. This may not be the greatest analogy, but you get the point (in reality, Zigbee performs really well, but inter-manufacturer interoperability has been cited as a problem).
Although Zigbee is open source, I don’t believe open source is right for this market. The market is too small. I want a standard by which all devices operate and Z-Wave offers this to me to a greater extent than Zigbee. Z-Wave is a standard (within each country), so when I buy a module from, say Jasco, I know it will work with my Vera 2 controller. Furthermore, I like some of the backwards compatibility aspects of the Vera 2 in particular, potentially allowing me to add less expensive X-10 (and INSTEON) modules. The fact that Z-Wave is not open source is not an issue for major corporations like Verizon and ADT, who both either have or are coming out with Z-Wave home control systems. In order to make an investment in these companies, one has to believe that these companies believe that the technology will survive, even in the event of a hiccup by Sigma Designs (Mitsumi will now also produce Z-Wave chips).
Finally, the upfront cost for a Z-Wave controller that I can easily operate over my iphone is $250 vs. the $600 upfront cost for a controller from Control4. Z-Wave is really more in line with my home automation needs. The more I read, the more impressed I became with Zigbee, and the more I was convinced that I would need to hire someone to install the system. With Z-Wave, I am more confident that I will be able to setup and maintain my network myself, at a lower cost. All the positives for Zigbee aren’t necessary for what I am going to do with my home, and at the end of the day, operation and cost (in that order) are what matter to me.