The Race Is (Still) On: ZigBee vs. WiFi for Smart Energy Homes

In the race between the wireless standards ZigBee and WiFi to network homes to enable smart energy management, ZigBee has so far taken the lead. But that doesn’t mean that Wi-Fi is giving up its push into the smart energy home. The two camps have made much of their comparative advantages in the field — but at the same time, both are working on making their technologies interoperable. So which is better for home energy management?

In my weekly update at GigaOm Pro (subscription required), I lay out recent interviews with both the ZigBee Alliance and the Wi-Fi Alliance to demonstrate where the two differ and where they work well together, as well as with the Electric Power Research Institute (EPRI) on its research into both. Here are some conclusions:

Market penetration: Most smart meters that are being deployed in North America have ZigBee radios to communicate with home energy devices. Wi-Fi’s penetration has been limited to wireless thermostats and other devices — though the ubiquity of Wi-Fi in the home could push more energy-aware devices to support it.

Cost: ZigBee was built with low-power sensors and controls in mind, and has much lower processing, memory and power requirements than Wi-Fi as a result. The Wi-Fi Alliance counters that its members are hard at work on lower-power chipsets that could compete with ZigBee’s advantages there.

Robustness: ZigBee device makers have overcome early problems with smart meter-home device connectivity by boosting power from 10 milliwattsvolts to 100 milliwattsvolts, the maximum allowed for the unlicensed 2.4GHz spectrum in which it operates. Still, as Craig Rodine, EPRI technical executive, told me, ZigBee will have to compete against other technologies in that spectrum, including the latest iteration of Wi-Fi known as 802.11n. EPRI has analyzed tested the technology, which is capable of streaming video and longer-range applications, and “it tends to win in a foot race” against ZigBee, he said.

Interference: Last year, EPRI did a test of ZigBee communications in a single-story ranch home in Pleasanton, Calif., and found that the network had trouble reaching certain areas, a problem caused both by physical obstacles like the chimney and electromagnetic interference from devices like microwave ovens.  The ZigBee Alliance says that its technology has built-in frequency agility and inter-packet spacing to allow it to work amidst interference. It’s also a mesh networking technology, meaning that every in-home device can also help propagate the network around obstacles.

Interoperability and ubiquity: The first version of ZigBee’s energy-specific technology, Smart Energy Profile 1.0, had some problems with ZigBee Alliance-certified devices failing to interoperate, EPRI’s Rodine noted. The new Smart Energy Profile 2.0 is meant to solve that problem, and Rodine suggests that ZigBee’s work with the Wi-Fi Alliance — including the creation of an Internet protocol (IP) stack for SEP 2.0 — is part of that effort. After all, the Wi-Fi Alliance has one of the most trusted certification regimes in the world, with tens of thousands of certified devices that have proven interoperability.

Of course, neither ZigBee nor Wi-Fi backers claim that they’ve got the end-all, be-all technology for networking energy-smart homes. Combinations that use Wi-Fi as a backbone and ZigBee as a link to multiple end-points are likely to see greater adoption as both teams work to integrate their technologies. To read the rest of my post check out GigaOM Pro.

Image courtesy of rotorboard.

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