Can "Smart" Lamps be "Energy Efficiency Dumb?"

Wed, 05/27/2015 - 16:17 -- MrGreen

A recent product group to join the expanding Internet of Things (IoT) family is internet-connected or "smart" LED light bulbs*. Recently, the U.S. Environmental Protection Agency (EPA) formally recognized the future growth potential of smart lighting by adding requirements for "connected" product to its latest ENERGY STAR Lamp and Luminaire program draft specifications. But, do smart bulbs mean good news for efficiency? Maybe not.

While the ability to control one’s lights from anywhere in the world could deliver positive efficiency results (for example, turning off lights left on by mistake or when not needed), recent testing by the International Energy Agency’s (IEA) Electronic Devices & Networks Annex (EDNA) group revealed that not all smart bulbs are created equal when it comes to standby power consumption (i.e. the bulb is emitting no light but remains connected to a network). Some smart bulbs unnecessarily consume high levels of standby power, decreasing the bulb’s overall efficacy (lumens per watt) to a level close to the incandescent bulbs they were designed to replace.

The table below shows the test results of eleven different lamps that were purchased in late 2014.

IEA EDNA Smart Lamp Test Results

Source: Smart Lamp Testing – Initial Results – IEA EDNA, Feb 2015

Models 1, 5, and 6 were supplied with a separate “bridge” which creates the communications link between the local network containing the controlling application (i.e. WiFi) and the lamp network (i.e. ZigBee). Typically, a bridge can be used by several lamps. Model 11 actually had the bridge function built into the lamp itself, resulting in the highest standby power consumption.

The graph below shows the impact of adding the standby power consumption into the overall efficacy equation**. All but one lamp model had its efficacy reduced to less than that of a typical CFL bulb, with the worst performer’s efficacy reduced to that on an incandescent lamp.

Overall Lamp Efficacy (includes standby power consumption)

Source: IEA 4E Bright Spark Newsletter, Issue 8, April 2015

For more information on the smart lamp testing described above, click here. For links to other EDNA activities, click here. For information on the revised ENERGY STAR Lamp program specification, click here.

* Defined as wirelessly controllable LED lamps, **Models 3,8, and 10 were removed due to very low lumen output