In the race between ZigBee and Wi-Fi for networking energy-aware homes, GE is leaning toward the low-power winner. According to a GE white paper released Thursday, ZigBee uses less than half the average power that Wi-Fi does — a fact likely to cement its place as the main technology to link GE’s smart appliances and its Nucleus home energy hubs.
Consider it another notch in ZigBee’s home energy belt. Utilities around the country have chosen ZigBee as the preferred technology to link smart meters and devices in the home, largely on the strength of its low power requirements and cheaper chipsets compared to Wi-Fi and other technologies built for higher-bandwidth applications.
GE’s study found that ZigBee systems consumed just 0.39 watts over 24 hours, compared to Wi-Fi’s 0.87 watts over the same time, when set up in identical configurations that will be typical of home energy-networked devices of the future.
That difference in power use is pretty minor compared to overall energy use of energy-hungry household loads such as air conditioners and refrigerators. But the choice of which technology to roll out to millions of smart thermostats, appliances and other devices adds up quickly — for one billion devices, it added up to 370 megawatts, or $315 million in extra power costs, the report noted.
Fractions of a watt also add up when calculating standby power, David Najewicz, manager of external technology programs for GE Appliances, noted in an interview. The European Union has set a standby power goal of less than 1 watt per device, for example, a level at which the difference between Wi-Fi and ZigBee’s power draw becomes an issue, he said.
Wi-Fi is far from locked out of the home energy market with this news. Other companies, such as Radio Thermostat, are launching Wi-Fi enabled smart thermostats. In the meantime, developers such as GainSpan are designing Wi-Fi chips that could compete with ZigBee chips on low-power performance, and perhaps on price. But right now, ZigBee chips now cost about $2 to $2.50 less than Wi-Fi chips, a price difference that’s likely to grow as ZigBee chip manufacturing ramps up, Venkat Venkatakrishnan, GE Appliances’ R&D director, said in an interview.
Wi-Fi will still play a role in GE’s home energy networking plans, Venkatakrishnan noted. The Nucleus home energy hub, which is expected to come out in retail tests in the second half of 2011, will have Wi-Fi capability to link to networked devices such as PCs in the home.
Still, ZigBee looks set to remain the technology of choice for linking everything else in GE’s Home Energy Management portfolio, unless an even more energy efficient wireless technology comes along, Venkatakrishnan said. Indeed, GE announced Wednesday that its Nucleus has earned the ZigBee Alliance’s first certification as a gateway device capable of handling other ZigBee-certified products. No doubt it’s just the first of a host of energy gateways, hubs, other devices built to accommodate ZigBee as a dominant standard for home energy management.
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