If your home has a garage, there is a good chance that you have an automatic garage door opener. Because these electrical appliances operate for only a few minutes per day, they don’t use much electricity to open and close your garage door. But there’s a catch: most garage door openers use three to five times more energy during the 1,437 minutes per day when they are “off” than they do during the 3 minutes per day when they are on.
Like any appliance that has a remote control, a garage door opener is always on. Even when it isn’t operating, it is warm and humming, listening for the radio signal that will tell the machine to spring into action. This type of electrical draw is called a “phantom load.”
Back in the 1950s, electrical appliances didn’t have phantom loads. When you turned them off — by flipping a toggle switch or knob that made a satisfying click — they were really off. Since then, however, appliance manufacturers have gotten sneaky. Even though the switch position may be marked “off,” the appliance is still warm. The only way to really turn it off is to pull the plug out of the wall.
Appliances with phantom loads include anything with a remote control, as well as any appliance that has a clock display or glowing LEDs. Appliances with phantom loads include a few obvious candidates, like set-top cable boxes, and several less obvious ones, like some washing machines and kitchen ranges.
In 2002, Mark Pierce, an energy expert at Cornell University, estimated that phantom loads cost the average U.S. household $200 per year. Other estimates are much lower, ranging from 329 to 569 kWh (about $40 to $70) per year. According to a web page on phantom loads maintained by the Lawrence Berkeley National Laboratory (LBNL), phantom loads typically represent “5-10% of residential electricity use in most developed countries.”
Since college students are heavy users of microwave ovens, computers, and electronic gadgets, student housing has higher phantom loads than average. A research study investigated phantom loads at an apartment complex near the University of Oregon campus in Eugene; the researchers found that phantom loads averaged 33% of the total electricity use in the apartments.
The more gadgets your house has, the higher your phantom load. Although the number of gadgets per U.S. home continues to grow, there is some good news on the phantom load front. In response to government regulations and prodding by the Energy Star program, some appliance manufacturers have reduced the standby power requirements of newer appliance models.
How much electricity do garage door openers use when they are off?
To return to the main topic of this blog: should you worry about your garage door openers’ phantom load?
One online source claims that “garage door openers can consume as much as 10 watts while they sit and wait to be activated by the car remote.”
As it turns out, the standby power use of garage door openers is all over the map. Curt Kinder, the managing engineer at Greener Solutions Air in Jacksonville, Florida (and a GBA reader), calculated that the phantom loads at his home (which includes three garage door openers) amounted to 5 kWh/day, or 25% of his home’s total energy use during the months when he wasn’t operating his heating or cooling systems. That amounts to 1,825 kWh per year. (Depending on the cost of Kinder’s electricity, his phantom loads probably cost him more than the $200-a-year estimate for average phantom loads made by Mark Pierce at Cornell.)
Kinder posted some comments on his residential phantom loads in a web forum, noting that “5 kwh/day exceeds the total usage of our entire kitchen: fridge, chest freezer, range, dishwasher, etc. … We have three garage door openers, specifically Overhead Door Phantoms. They are quiet and have been relatively trouble-free. Imagine my shock at learning each uses 14.5 watts while sitting and doing nothing. Doing the math, the three (aptly named) Phantoms have cost us $200 in standby power since we built the house in early 2008.”
Of course, Kinder isn’t the only homeowner who has measured his garage door opener’s phantom load. A homeowner who posts comments under the nickname “A.Z. Doug” posted a comment on Amazon.com about a garage door opener manufactured by Genie. He wrote, “This Genie garage door opener system draws a whopping 8 watts of standby power, every hour it is plugged in, whether it is doing anything or not. That’s 70 kWh a year for doing nothing. If you have two or three doors on your garage, do the math.”
Measurements made by Lawrence Berkeley National Laboratory
Researchers at LBNL measured the standby power draw of 34 garage door openers. The watt draw of these units (when off) ranged from a low of 1.8 watt to a high of 7.3 watts; the average power usage when off was 4.48 watts.
Clearly, the researchers missed a few models, including Kinder’s 14.5-watt energy hog. Here’s a table summarizing the phantom load of garage door openers.
Annual phantom load of garage door openers (assuming 12.5¢/kWh electricity)
|•||Average annual energy use for one garage door opener||Average annual energy use for two garage door openers|
|Most efficient model measured by LBNL||15.8 kWh ($2)||31.6 kWh ($4)|
|Average of all models measured by LBNL||39.2 kWh ($5)||78.4 kWh ($10)|
|Least efficient model measured by LBNL||69.9 kWh ($9)||139.8 kWh ($18)|
|Curt Kinder’s energy hog model||127.0 kWh ($16)||254.0 kWh ($32)|
When garage door openers are operating, they draw between 400 and 500 watts; units with high-wattage light bulbs use more than units with CFLs, of course.
Some newer models are getting better
Although it’s still possible to purchase a garage door opener with a phantom load of over 5 watts — in other words, an energy hog model — some newer models are better designed. To learn more, I spoke with Ron Brogle, the marketing product manager for LiftMaster. (LiftMaster is a division of the Chamberlain Group, a manufacturer that markets its garage door openers under its own name as well as the Craftsman, Sears, and Wayne Dalton brand names. The other major U.S. manufacturer of garage door openers is Overhead Door Corporation, which markets its products under its own name as well as the Genie name).
“Historically, most garage door openers are sitting there idle, consuming quite a bit of power,” Brogle told me. “Across the board, we had seen, in our products and others’, that garage door openers drew 5 to 8 watts in standby mode. What we have done here at LiftMaster is to attack that. A lot of the openers had transformers that were sitting there creating waste heat. So we converted to a switch mode power supply, and we targeted the electronics. Our newer models shut down unnecessary circuitry during idle mode. Of course the radio receiver is alive, but we power down everything else. Some of our newer models are down to around 1 watt on standby.”
According to Brogle, the LiftMaster garage door openers with the lowest standby loads are the LiftMaster 8360 and the somewhat more expensive LiftMaster 8550 — both of which have DC motors — and the LiftMaster 8355, which has a 1/2-horsepower AC motor. I plan to measure the standby power use of several models of garage door openers during the next few weeks; I will report my findings in a future blog. [Addendum: According to my measurements, the LiftMaster 8550 has a standby power draw of 3 watts. For more information on my measurements, see the postscript at the end of my blog about washing machines.]
I also invite GBA readers who have measured the standby power use of garage door openers to share their findings.
Hooking up your garage door opener to a solar panel
If you enjoy tinkering, you may be tempted to buy a battery-equipped garage door opener that is designed to operate during power outages. (Most major garage door manufacturers now offer models with battery backup.) Because these garage door openers have DC motors, they can be disconnected from the power grid and hooked up to a small PV panel that charges the unit’s battery. (Of course, you’ll need to install a charge controller between the PV panel and the battery.) This jury-rigged appliance will be more likely to operate well through stretches of cloudy weather if you add a second (larger) battery, wired in parallel to the factory-supplied battery.
More information on off-grid garage door openers is provided in an entertaining YouTube video on the topic.
Are we gaining ground or losing ground?
Is the average phantom load in U.S. homes growing or shrinking? According to LBNL, “It’s probably growing. Programs directed at consumer electronics have stimulated manufacturers to cut standby power use in many products. At the same time, the number of new appliances that continuously draw power is increasing rapidly.”
In other words, we are winning a few battles, but we’re probably losing the war.
Do we really need garage door openers?
Garage door openers are a useful convenience, especially for the elderly and handicapped. But I would be derelict in my duties as a green advice columnist if I didn’t mention that our grandparents didn’t have garage door openers. If they needed to open a garage or barn door, they got out of their cars, or dismounted their horses, and opened the door the old-fashioned way.
This type of daily exercise helped keep our grandparents slim and fit.
Martin Holladay’s previous blog: “Keeping Cool in a Two-Story House.”