Putting the Meter Under the Microscope
How a smart-meter kit changed my energy habits
When you hire a detective, sometimes you find out things you don’t want to know. That’s true of smart power meters just as much as it is for the traditional gumshoe and telephoto lens variety.
Our local utility is planning to install smart meters some time this year—perhaps—but how much of the information the utility will share with customers is still unclear. So I reckoned that having our own smart power unit could be a good investment, and certainly an intriguing project. When IEEE Spectrum got a residential TED 5000 Energy Detective unit for review, it all seemed very straightforward: Attach a monitoring unit to my home’s electrical distribution board, see where the energy was going, take steps to reduce waste, and reap the financial rewards.
The first hitch I ran into was right at the beginning of the installation instructions, which start by telling you to open up your distribution board and attach voltage-sensor wires to two successive spare circuit-breaker positions. Our mid-’70s house ran out of spare breaker positions not long after construction and has since had two subpanels added. Although I do have a few spaces in the subpanel on the other side of my house, the kit also comes with two current-sensing-loop clamps that need to be placed around the phase A and phase B main feed lines into the house.
As it turns out, this problem wasn’t insurmountable: What the instructions actually mean is that you need to make contact with one of phase bus bars and the neutral bus bar in the panel to get accurate readings. I sensibly let an electrician take care of that chore while he was here doing some other work, so it added perhaps US $15 to $30 to the cost of the smart meter kit, which was $240 for my version, the TED 5000-C. The C version comes with a dedicated display; you can also get a kit for $200 without a display from the makers, Energy Inc., based in Charleston, S.C.
The sensors connect to a measuring and transmitting unit. This unit uses a power-line communication protocol to transmit data to a gateway, which plugs into a spare wall socket. The gateway, in turn, transmits wirelessly to the dedicated display, a tiny portable unit with a monochrome LCD and a mode button that displays current or cumulative power consumption in kilowatt-hours or dollars. This display has to be closer to the gateway than you’d think—within about 10 meters—for it to work.
Fortunately, the gateway also has an Ethernet port. I used the port to wire the gateway to my local area network. That’s when the fun really began. An installation utility (available for Microsoft Windows and Apple’s OS X) gave me the network address of the meter; directing a browser to that address served up a Web page with a real-time display of kilowatts, volts, dollars per hour (assuming you tell the software your electric rates), and so forth. Additional pages offer usage charts. The system stores recent measurements about every 2 seconds. It saves several months of older measurements with a minute-by-minute history.
It was great fun walking around with a tablet connected to my local network via Wi-Fi, turning off lights and watching the colorful little power consumption gauges go down. But it was also a little sobering to see just how much it cost to leave a pull-chain light burning in the far dark corner of the basement.
Worse yet, after the first kilowatt or so of savings, the easy pickings for reducing consumption stopped. If you work at home, your PC is going to be on all day. Figure a couple of hundred watts for that right there. If you have a digital video recorder to save your favorite shows, it’s going to be on too. Routers, switches, hubs, laptop and tablet chargers, smoke detectors, cordless phones—they all consume power throughout the day.
Even when nominally off or in standby mode, many devices continue to consume a fair amount of electricity, costing the average U.S. home $100 per year according to the United States’ Environmental Protection Agency. Unplugging these devices is a lifestyle change I’m not willing to make. Then there’s the washer, dryer, refrigerator—the list goes on—the abandonment of which would mean even more radical lifestyle changes.
And in a house built during the late 20th century, there’s even more power consumption from electrical equipment that would be difficult to unplug even if I wanted to: the motorized pump that sprays a mist of oil through the furnace burner, the motors that push air or water through the heating system, and in our case, even a motor that pumps wastewater uphill to the city sewer system. None of these is optional in a house designed for them. In total, it all adds up to a baseline of 10 to 15 kilowatt-hours every day.
Should I be surprised that a household with a lot of electrical gadgets and appliances consumes a lot of electricity? Probably not. But the Energy Detective display right next to the dining room table makes it harder to just go on about my everyday business. Flicking the light switch down as I leave a room is becoming more of a habit, those LED bulbs in the hardware store are looking more attractive, and I may even figure out some way to control that light at the other end of the basement that involves neither climbing gear nor calling in an electrician. And ultimately (in addition to the actual savings in energy bills), that mindfulness may be the best thing.
This article originally appeared in print as "Parsing Power."
A correction to this article was made on 11 March 2013.