Want CNET to notify you of price drops and the latest stories?

Info-starved no more--home energy gadget clues you in

Energy monitoring is like fitness-tracking for your utility bill. CNET's Martin LaMonica tries a whole-house electricity monitor out and gets a read on where software and the cloud is taking home energy.

Martin LaMonica Former Staff writer, CNET News
Martin LaMonica is a senior writer covering green tech and cutting-edge technologies. He joined CNET in 2002 to cover enterprise IT and Web development and was previously executive editor of IT publication InfoWorld.
Martin LaMonica
5 min read
A looking glass into your electricity meter--a sensor that reads data and send it to a Wi-Fi gateway for reading online. Martin LaMonica/CNET

You may think you know how much electricity you're using, but there's a whole lot more you could--and should--know.

Despite living in the information age, most of us are basically in the dark when it comes to electricity bills, with just a rough idea of how much we consume every month and what it will cost.

Over the last few weeks, I've been testing a whole-house energy monitor from startup Wattvision, which actually answers basic questions, such as how much and when you consume electricity and how it trends over time. I also hooked up my home's real-time electricity feed to another startup's analytics Web service called PlotWatt to get more detail on what's consuming energy.

How to get electricity meter data online (photos)

See all photos

A couple of hardware gadgets made it all possible, but using the services showed me that a lot of the action in home energy is moving to software and up into the cloud. In the case of energy monitors, back-end analytics can provide insights and recommendations a simple metering device can't. And if you have a smart thermostat or home automation system, you can remotely control your heating, cooling, lights, and appliances from a smart phone or PC.

But before getting into the gadgetry, one has to ask: why bother with energy monitoring? Is it green? Does it help me lower my bills? Is there a good payback?

Having played with Wattvision and other whole-home monitoring devices, I'd say the main motivation is simply to be better informed. Just as people go online to check their bank account or credit card balance, energy monitors can help you avoid unpleasant surprises when the monthly bill comes.

As these products mature, though, I expect the features and potential energy savings to improve. Having a single device or service to monitor electricity, home gas, and water meters is also likely to happen.

This week, we got a glimpse of where energy monitoring is going. As part of the White House's Green Button initiative, three California utilities are now letting consumers download detailed electricity data collected by smart meters and are encouraging software developers to build applications with that information. The apps they showcased visualize and analyze meter data so people can, for example, decide which electricity rate plan is best, whether it's worth getting solar panels, or compete in online energy-savings competitions.

Watts under the hood
For those of us who don't have smart meters, though, energy monitors do the job of collecting real-time electricity data and putting it online. In the case of the Wattvision system, it wasn't too complicated, although my impatience with reading directions did require a couple e-mails to CEO and founder Savraj Singh. After about a half an hour, I was able to use my tablet or PC to view a data graph of electricity usage and money spent in real time and later, by day or by month.

Wattvision has an optical sensor that you strap onto an electricity meter that reads every watt-hour that passes through. You then need to run a thin cable from the sensor to a Wi-Fi gateway inside. The gateway, which is about the size of a wallet, uses a home Internet connection to transmit the data online.

Once the gateway starts transmitting, you set up an account and voila, you can see your wattage in real time. The application gives you historical data and lets you view usage both in watts and money. It also tells you how much electricity you consume compared to others.

Overall, the set-up was straightforward and the instructions were good. The most difficult things might be identifying what type of meter you have or finding your router's IP address.

As you might expect, I studied the data graphs carefully at first, noticing how the refrigerator goes on every half hour and how the dishwasher causes a big spike. As the weeks passed, though, I checked only occasionally to compare one month to another and to make sure the "baseline" power use wasn't higher than normal.

The system is responsive enough to give you a good idea of how individual changes affect the total. If you turn on the electric heater or even flick off a couple of lights, the Wattvision readout will quickly change. This is, after all, the point: when you can see how much leaving the TV on when no one's in the room is costing, you're more motivated to change your behavior.

If you're a hard-core energy geek, you could take the Wattvison data and, for example, calculate how much money and emissions you'd save by using a clothes line to dry clothes, as one customer did. But even if you're just mildly curious about your home energy, the graph and data help give you context.

Armchair energy hawk
It turns out I'm a special case because my house is equipped to solar photovoltaic panels and the Wattvision sensor can't tell whether the house is pulling power from the grid or feeding into the grid from the panels. That's where PlotWatt came into the picture.

Using the API of Wattvision or other monitors, PlotWatt analyzes the trends in your power graph to figure out what the big energy users are. It can tell you confidently how much of your monthly bill your refrigerator is taking and what the "always on" power draw is. Seeing how much I spend just on vampire or stand-by power prompted me to consider what could be turned off.

What impressed me most, though, is that the software figured out that I have solar panels by studying the feed from Wattvision. Although I need a different kind of meter to separate the solar output from the other data, it demonstrates some of the potential of pattern-recognition software. Software like this could, for example, uncover that your air conditioner is sucking up more energy than it should and alert you that it's time for a tune-up.

The Wattvision system with the sensor and Wi-Fi gateway costs $249, about the same price as a competing product, the PowerCost Monitor and Wi-Fi connection. PlotWatt is free to consumers and the company is trying to make money with fee services to businesses with multiple buildings.

Many early adopters of whole-house energy monitors say these gadgets pay for themselves within a few months. But whether these sorts of tools help you change your behavior really depends on the person and electricity load.

In general, the bigger your electricity bills, the more likely you'll find ways to save. The opposite is also true: if you already make an effort to cut back on waste electricity, this sort of gadget probably won't have a quick payback. On the other hand, you'd never really know without measuring it.