In recent years, the technology of our cars has advanced at a more rapid rate than the technology of our homes. A new car’s dashboard has gauges that display all kinds of information, including the amount of fuel in the car’s tank, the oil pressure, the electrical system voltage, and sometimes the tire pressure. Many new cars even have a real-time fuel-efficiency gauge that displays miles per gallon.

If you’re interested in comparable information about your home, you’ll probably have to go down to the basement and look at the float gauge on the top of your fuel oil tank. Then you can go outside and read the gauge at the top of your propane tank. Next, stick the prongs of a multimeter into an outlet to verify your electrical system voltage. And if you want electrical use data, you can wait until you get your utility bill at the end of the month.

It will probably be many decades before most homes have such car-like features as electrically operated windows or dashboards that indicate whether the doors are latched. But technology-savvy homeowners can already install a real-time whole-house electricity meter with a display for the kitchen or living room wall. Often referred to as “energy dashboards,” such monitors are available for less than $200.

You can even buy a more sophisticated dashboard that displays electricity, natural gas, and water use — although the cost of the required monitoring equipment rises steeply with these added features, into the thousands of dollars.

Documented energy savings
Studies have repeatedly shown that homeowners do a better job of conserving energy if they get real-time energy-use feedback. If you can see how many kilowatts your house is consuming, you’re more likely to check whether you accidently left the basement lights on.

• In a March 2006 paper, “The Impact of Real-Time Feedback on Residential Electricity Consumption,” researcher Dean Mountain, a professor of economics at the McMaster Institute for Energy Studies in Hamilton, Ontario, reported data from an energy-dashboard study conducted by a Canadian utility, Hydro One. On average, the 400 Ontario households that received a PowerCost whole-house electricity monitor reduced their electricity usage by 6.5%. Mountain noted, “An important observation from the study is that the behavioral response remained persistent and did not decrease over time during the study period.”
• In an April 2006 paper, “The Effectiveness of Feedback on Energy Consumption,” researcher Sarah Darby reviewed published studies of savings attributable to electricity and natural-gas dashboards. “The literature reviewed here mostly consists of primary sources, with a few review papers. The focus is on feedback on gas and electricity consumption,” she wrote. “The norm is for savings from direct feedback (immediate, from the meter or an associated display monitor) to range from 5%-15%.”
• An article titled “Evaluating Energy Use Feedback Devices,” published in the July/August 2008 issue of Home Energy magazine, reports the results of a Florida study of electricity-use monitors. Three researchers from the Florida Solar Energy Center —Danny Parker, David Hoak, and Jamie Cummings — measured electricity savings in houses equipped with an electricity monitor called The Energy Detective. After correcting the data for reductions in energy use that were weather-related, the researchers concluded that the homes with energy monitors had average electricity savings of 7.4%.

These are good numbers
It’s hard to think of any other $200 device capable of reducing a home’s total electricity use by 6.5% to 7.4%. Occupant decisions are responsible for huge variations in energy use from house to house — even when the houses being compared have similar specifications. These energy monitors help homeowners see (and reduce) their energy use as it happens.

I’ve been living with a whole-house electricity meter for at least 16 years. (Since my house is off-grid, I use a Bogart TriMetric meter.) There’s nothing like real-time feedback to encourage conservation. Every now and then, I notice an anomaly. I’ll mutter, “Holy smokes, that's a lot of amps!” and scurry around the house trying to figure out what’s been plugged in.

For those looking for green points, the National Green Building Standard (ICC 700) provides up to 4 points for the installation of a residential energy dashboard (see sections 703.4.9 and 705.1).

The cost-effectiveness question
If a homeowner pays $100 a month for electricity, the installation of a $200 electricity dashboard that helps the owner reduce electricity use by 5% will pay for itself in less than 3 1/2 years. That’s a fairly fast payback.

The payback for more sophisticated monitoring systems — especially those that monitor electricity, water, and natural gas — is likely to be more elusive. According to a recent article by Jeffrey Lee, “Proving a return on investment is still an obstacle. … AgileWaves’ typical whole-house gas and electric monitoring system with details on seven circuits retails for $7,500, and prices can range higher or lower depending on capabilities.”

Choosing an electricity-use monitor
The two most prominent electricity-use dashboards are The Energy Detective and the PowerCost Monitor from Blue Line Innovations.

The Energy Detective is a whole-house monitor that displays real-time electricity use in kilowatt-hours (kWh) or dollars per hour. It also shows how much electricity has been used since the beginning of the billing period.

The Energy Detective has two components: a transmitting unit mounted in the electrical service panel, and a receiving/display unit installed in a convenient location, such as the kitchen or living room. The transmitting unit sends data to the display unit through the home’s AC wiring.

To provide power to the transmitting unit, two leads must be connected inside the electrical service panel; the black lead goes to a 15-amp or 20-amp circuit breaker, and the white lead goes to the neutral bus bar. The unit also has two clothespin-like current transformers that need to be clamped onto the main cables entering the service panel from the meter.

The Energy Detective computes power draw in kW every second. The display shows both instantaneous power use and cumulative energy use for the month. Model 1001 — the basic model, designed to handle 200-amp residential service — can be ordered from the Energy Detective Web site for $120.

The PowerCost Monitor
The PowerCost monitor consists of two battery-powered units: a sensor/transmitter unit and a display unit. The transmitter attaches to the outside of an ordinary cylindrical utility electricity meter by means of a ring clamp, while the display unit is installed indoors. (Homeowners can easily install the transmitter without the help of an electrician.) Information is transmitted between the two units by radio waves.

The PowerCost monitor works with both electromechanical and digital utility meters. The monitor displays electricity use information in either kilowatt-hours (kWh) or dollars; it can be programmed to accommodate two-tier rate structures. Various display options are possible, including real-time consumption in dollars per hour or kilowatts, as well as total dollars or kWh consumed since the “clear” button was last pushed.

Unlike the Energy Detective monitor, the PowerCost monitor requires batteries for both the transmitting unit and the display unit. (Each unit requires two AA batteries.) Energy Federation Incorporated sells the PowerCost monitor for $109.

More electricity-use dashboards
Several other manufacturers offer electricity-use dashboards that compete with the Energy Detective and the PowerCost monitor:

• The ECM 1220 Energy Monitor is manufactured by Brultech Research in Saint Catharines, Ontario.
• The Insight energy monitor is manufactured by Tendril Networks in Boulder, Colo.
• The Power Monitor is manufactured by Black & Decker.
• The Energy Owl is manufactured by Grossman Innovations of Spokane, Wash.
• The Meter Reader is manufactured by Energy Monitoring Technologies in Miami, Fla.
• The Energy Hub Dashboard is manufactured by EnergyHub in New York City.
• The EnviroScape Energy Management and Control Panel is manufactured by BreezePlay in Charlotte, N.C.

Measuring water use
If you want a residential energy dashboard that measures both electricity and water use, the cost of the monitoring equipment goes up.

• The EcoConcierge from In2 Networks is a Web-connected monitor that can be configured to display real-time electricity and water use.
• General Electric manufactures the Energy Monitoring Dashboard — referred to in some GE literature as the Smart Panel or SmartCommand Dashboard. This device can be configured to monitor both electricity use and water use.

Web-based or software-based monitoring systems
While all of the above-listed manufacturers provide homeowners with physical display units to install on the living-room wall, other monitoring systems are Web-based or software-based. These systems live mostly on the Web, so they require homeowners to turn on their computers to find out how much energy the house is using. The systems depend on Web-enabled hardware from a variety of manufacturers to collect relevant data.

• The Google PowerMeter is a Web-based service to help homeowners monitor electricity use. The service will only work in homes equipped with certain utility-installed “smart” meters or with specific brands of whole-house electricity meters. For more information, see a recent GBA news article, or visit the Google PowerMeter Web site.
• The Greenbox Technology Energy Management Ecosystem is a software-based electricity management program. Greenbox Technology was recently acquired by Silver Spring Networks.
• AgileWaves Resource Monitor software displays data collected by monitoring devices from a variety of manufacturers. Unlike the other monitoring systems mentioned, AgileWave can keep track of natural gas use as well as water and electricity use — as long as the necessary (and expensive) Web-enabled monitoring units have been installed.

Monitoring systems for commercial and institutional buildings
The owners of large commercial or institutional buildings can often afford more elaborate energy-monitoring equipment than the typical homeowner. Systems designed for commercial buildings include:

• The Building Dashboard from Lucid Design Group in Oakland, Calif.
• The iBPortal Dashboard from Quality Attributes Software in Ames, Iowa.

A more complete list of energy dashboard manufacturers can be found at a useful blog post on the MapAWatt Web site.

Last week's blog: "The Uncertain Future of Phoenix and Las Vegas."