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Good science begins at home. I learned this the day the owners of a fancy automated house let me loose inside their place for an hour to check out their energy monitor. I ran amok, letting the jacuzzi fill up, burning toast for no reason, and flipping on and off an expensive plasma slab TV.

The results were intoxicating: a tabletop display in the kitchen showed pretty, Flash-animated bar graphs rising to an alarming crest, tallying an exact count of kilowatt-hours, gallons, and therms wasted, and tripping cute animations to point out that I’d used more resources than Al Gore’s mansion during a global-warming fundraiser.

Of course, the whole point of resource monitoring is to save energy. But it’s hard to ignore the allure of real-time feedback. Energy’s usually shrouded in mystery. Your bill comes once a month, and then who knows what caused a spike or trough in your consumption?

“People need constant reminders of what’s going on in their houses, and monitoring your usage can have a big impact on behavior,” says Ed Lu, lead engineer of Google’s energy monitoring group and a former NASA astronaut. “If I took the speedometer out of your car, you could guess at the speed pretty close, but not that close.”

What I learned from my hour of prodigal excess, however, is that instantaneous data is only the beginning. If I were an actual occupant of the house, I would have been looking at the historical trends and the energy display’s little advisory messages all along.

It’s the richness of the data that makes it useful. After all, Cadillacs sported simple gas mileage displays back in the 1970s, but it was the triumph of the Toyota hybrid user interface that gave us the “Prius effect”: a graphic, 30-minute historical trend display that pushes drivers to new MPG goals.

In a household setting, analysis needs to be even more sophisticated. A good energy monitor will let you filter out high-wattage appliances like toasters or hot glue guns that are only on for a short time, and reveal pesky resource hogs like faulty pool pumps, hibernating desktop PCs, always-on stereo receivers, and failing fridges that cause long-term waste.

Says Collin Breakstone, VP of business development for Agilewaves, whose Resource Monitor was designed by former NASA engineers: “Because of our background in mission-critical data acquisition systems, we know how to handle massive amounts of data and display it in a meaningful, actionable way.”

We’ll need it, especially as home energy pricing becomes more complex. Utilities around the country are starting to offer residential customers the option of a time-of-use rate, in which power becomes less expensive after peak hours. There are also tiered-rate plans, in which you pay less per kilowatt-hour if you bring down your overall consumption. Utilities eventually want to move to real-time pricing, which will fluctuate directly with the market.

To sort through the options, energy monitoring systems like those from startup Greenbox send personalized messages to your web browser, such as: “Your base load increased by 60 watts yesterday. You would save $162 a year by switching electricity plans.”

Such straightforward advice is a bonus for home-owners attuned to environmental concerns. And people like to save money. But will the money saved on a typical $100 bill (maybe 15 bucks a month) motivate everyone?

“No one really knows how much people would be willing to change their behavior,” admits Michael Murray, CEO of monitor maker Lucid Design Group. “It’s not going to be the early adopters who will help us get out of this mess; you have to engage the rest of the population.”

To reach the wasteful masses, Lucid created an energy interface that pits users against one another — and buildings against one another — in a game to see who can expend the least wall juice.

“Competition is a powerful way to motivate people,” says Murray. “What some people really want is bragging rights. It’s about being number one, not necessarily all about saving the planet.” Lucid currently installs most of its systems in university dorms, where it sees very good participation in its intramural energy contests.

Meanwhile, other companies are contemplating the competitive drive too. Google’s PowerMeter system needs widespread installation of smart electric meters to gain ground, but then users will be able to share their data in many different ways.

“I’m sure we’ll see throw-downs of one city versus another city,” says Google’s Lu. “How about Stanford versus Berkeley?”

After experiencing the immediacy of real-time data firsthand, I wanted a dashboard for my own house. And if I couldn’t afford it, I would rig one myself. Here’s a representative sample of various options available:

Agilewaves Resource Monitor

A complete system for homes and commercial buildings. Comes with electricity, water, and gas hardware from industrial suppliers, and a gateway that translates various bus signals from sensors into standard IP protocol. An on-site server (about the size of a Mac mini) or remote host captures and analyzes signals, then displays the data on cellphones and desktops, and automatically instructs subsystems to open motorized windows or fire up heating systems (Figure A, following page).

Availability: Now; Cost: From $7,500

Lucid Design Group Building Dashboard

Monitors mainly electricity, and the company works mainly with college campuses. The Building Dashboard Starter product comes with an amp sensor that requires installation by an electrician.

The sophisticated interface shows real-time consumption, historical trends, translation into novel and surprising metaphors, and competition statistics between dorm buildings (Figure B).

Availability: Now for big customers; pilot program for residential customers; Cost: From $9,950

Google PowerMeter

A pretty face for data that’s been harvested and logged by your utility’s smart meter. For consumers outside smart meter installation areas, Google software may be compatible with upcoming pre-packaged home electricity sensors. PowerMeter will also be open and hackable for anyone else. “We’re hoping that the DIY community creates new uses of their own,” says Lu (Figure C).

Availability: Mid-2009 for limited U.S. utility customers; Cost: Free


A clean, web-based interface written with Flash software (company founders are the inventors of Flash). Excellent advisory data on payback performance of solar electric and hot water systems. Wireless thermostats connected through ZigBee or low-power wi-fi respond to web requests you make (Figure D).

Availability: Limited utility customers; Cost: Service is free; smart meters underwritten by local utility, or purchased by DIYers

Tendril Residential Energy Ecosystem

A flock of mesh-networked gadgets that talk to each other and report to the Tendril server, giving you a detailed picture of consumption. The ZigBee-based wireless network includes a thermostat that can respond to user-designated rules and utility price changes, and outlet adapters that report real-time power use by receptacle — giving a clearer picture of what or who is using the most watts than single-point smart meters could (Figure E).

Availability: Limited utility customers; Cost: Basic setup underwritten by local utility, outlet adapters extra

Do-It-Yourself Options

For companies and individuals alike, hardware is the biggest hurdle to resource monitoring. Most usage sensors are expensive industrial models that output a variety of exotic data bus protocols. For instance, the cheapest way to measure water or gas flow is a $300 in-line meter that requires professional installation and custom programming. Doppler sensors that clamp on the outside of pipes and gauge flow using ultrasound are available, but still spendy (over $1,000). Electricity sensors are the least expensive and the easiest to install.

Availability: Now; Cost: From $80

» For instance, to hook up Energy, Inc.’s The Energy Detective ($144), you clip an electromagnetic sensor to the incoming power lines inside your service panel. You can then view usage on its wireless tabletop display, or through the optional PC software or third-party software.

» Another gadget, Blue Line Innovations’ PowerCost Monitor ($119) involves strapping an optical sensor to the outside of your electricity meter and viewing the data wirelessly on a desktop LCD. (Blue Line doesn’t currently offer a method for crunching data with your own software.)

» Energy Optimizers Limited’s Plogg electrical outlet sensors are equipped with either Bluetooth ($95) or ZigBee ($80) to report back to your custom-coded database wirelessly.

» Some of the most inspired systems come from individual makers. For instance, the thrifty Tweet-a-Watt system (see page 112) combines the common Kill A Watt outlet sensor ($25) with XBee wireless communication modules ($23). Limor Fried originally created the network to collect power usage data from around her apartment in real time (Figure F).

The homebrew Bwired system from Dutch home-owner Pieter Knuvers ( harvests power, water, and gas data from dozens of off-the-shelf and self-made electrical sensors. Knuvers’ system registers every time his family uses the toilet, the bathroom scale, the refrigerator door, and the front door; it also adds up the precise energy used by every appliance in the house and organizes the data neatly online in bar graphs.

While I personally don’t need the kind of deep data mining he’s getting by cross-tabbing toilets, scales, and fridges, it’s nice to see that someone’s on the forefront of this new field of domestic research (Figure G).


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