Part 1 in our new series on managing and monitoring energy production and consumption in your home, apartment, or flat.
As the business adage goes, you can’t manage what you don’t measure, and that rings equally true in the home—particularly when it comes to energy consumption. If you are considering building or purchasing a zero net energy home or simply want to better manage the energy usage in your current home, apartment, or flat, you will need to get much more granular than the monthly electric utility bill if you want to begin unearthing what’s going on behind your electric meter.
[pullquote]It would be great if devices were intelligent enough to inform you when they were badly misbehaving with power usage, but until that technology trickles down … you will need some sort of energy monitoring tool.[/pullquote]Where do you start? One place to begin is by unearthing the energy vampires around your increasingly-smart home, those devices that are siphoning power through your meter even when they are asleep or otherwise at rest. It would be great if devices were intelligent enough to inform you when they were badly misbehaving with power usage, but until that technology trickles down into more of the individual devices themselves you will need some sort of energy monitoring tool.
One of our favorite tools for individual device monitoring is the relatively low-tech Belkin Conserve Insight, a straightforward, app-less, non-networked monitor that you simply plug into a wall outlet—then any 110-volt device connected through its power port can be monitored by looking at the Conserve Insight’s tethered LCD display. As we gathered data around the our labs, the $29.95 Conserve Insight worked well for taking instant energy usage snapshots in many areas.
In cases where we wanted to monitor energy usage over a longer period, we used networked smart switches—either the Belkin WeMo Insight or the iDevices Switch. While the primary function of these products is remote device control, their respective apps also display current and cumulative energy usage for the connected device.
In the case of our monitoring project, we selected representative devices throughout the home so we could begin to characterize their energy usage habits. As we moved around, we measured 33 different devices and small appliances when they were at rest or asleep, and again when they were in use (for items always-plugged in) or in their charging cycle (for portable, battery-powered devices). We collected a treasure trove of interesting data (see table) that was enlightening in both the at-rest and in-use ends of the energy usage spectrum.
At the head of our top-10 vampires list was an always-on Sonos Connect:Amp wireless audio amplifier that measured 18.6 watts at rest—and surprisingly, that device consumes only 18.9 watts when belting out our favorite tunes through the 4 speakers it powers. For all of the devices we measured at rest, the total energy consumption was 119.2 watts, or a total of 2.86 kilowatt hours over the course of day (that translates to 85 kilowatt hours in a 30-day month).
On the in-use measurement side, a four-slice toaster—at 1,814 watts—made the top of the list, but of course that level of energy usage is of a short duration while your bread or muffin is toasted, then it drops to a very low at-rest measurement (1.0 watts, to illuminate this toaster’s dual blue LCD displays).
So, what to make of all this data? Keep in mind it’s only a snapshot of selected energy-consuming devices in this home and we have not begun to dig into the major appliances, the heating/cooling system, water systems, and other components contributing to our overall energy footprint. We hope this approach to measuring may encourage you to begin unearthing similar data around your home—data that can help you better manage the energy consumption that manifests itself as charges on your electric bill. Look for much more from us in the future on this topic.
Brand and model
At rest (watts)
In use (watts)
Denon Integrated Network AV Receiver AVR-1913
Bowers & Wilkins ASW500
DocIt System with Electrolux vacuum motor
Keurig B70 Single-serve Brewing System
Apple iMac 27-inch Mid 2010
Dell OptiPlex 780 (no flat panel)
DJI Phantom II Battery Charger
Netgear ProSafe 16-port Gigabit GS116
External hard drive
Seagate 5TB Backup Plus
Garage door opener
Liftmaster 3800PLD Jackshaft Door Opener
Apple MacBook Pro 13-inch, Early 2011
Dell Inspiron 15R
Epson Stylus Pro 3880
DirectTV dish components
DirecTV Genie HD DVR HR44-500
DirecTV Genie Mini
Apple iPhone 6 Plus
Apple iPad 1
Apple iPad 3
Apple iPad Air 2
TV, LCD Flat-panel
Sony 40-inch KDL-40S5100
TV, LED Flat-panel
Samsung 55-inch UN55ES7100
Cuisinart Four-slice toaster CPT-190
Water recirculation pump
Taco Cartridge Recirculator 003-B4
Wireless audio amplifier
Wireless audio router
Wireless audio speaker
Wireless broadband radio
Ubiquiti NanoBridge M airMAX Bridge
Apple AirPort Express
Total energy usage at rest (watts)
“In use” measured when charging. The power bricks we tested generally did not consume power when no device was attached.
Table: At-rest and in-use energy measurement data for selected devices
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Tom Kolnowski is the Chief Content Officer & Founder of Digitized House Media, LLC, the publisher of Digitized House | Guide to the Connected Home. When he isn’t writing about smart home technology, sustainability, and high-performance architecture, you’ll find him exploring faraway destinations with his family.