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With new monitors, homeowners can keep track of their electricity use in real time. It can make all the difference.

By RUSSELL GOLD

Tom Tassi's $300 electricity bill had become an embarrassment.

"It was a joke," says the Kenosha, Wis., resident, who runs a six-person computer-service company. "The lady across the street would bring her electric bill to show me," he says. Her bill, for a similar house, was less than half what he was paying.

Over the years, he replaced his windows, electric furnace and refrigerator with energy-efficient models. His local utility performed two energy audits. He added insulation. "I can heat the inside of my house with a lighter," he says.

But his bills remained high. That's when Mr. Tassi became an early adopter of home-electricity monitors—using the new device to figure out exactly where the waste is in his home, and how he can reduce his bills.

Unlike smart meters, which allow homeowners to view their total usage only after a delay, home-electricity monitors tell consumers specifics about their energy usage and what it's costing them in real time. The device connects to a home's breaker box, from which it wirelessly transmits the information to a smartphone-like display unit.

Moving around the house with the hand-held device, homeowners can immediately see the difference that each light or appliance makes in their total power consumption and bill. They can also view the data on the web using software that comes with the monitor or free online tools such as Google Inc.'s PowerMeter and Microsoft Corp.'s Hohm.

Such knowledge could have a profound impact on power consumption. Homeowners who can monitor their total home-electricity usage in real time cut their power consumption an average 9.2%, according to a survey of 36 studies by the American Council for an Energy-Efficient Economy, in Washington, D.C. And when homeowners have real-time feedback down to individual appliances, the savings were 12%.

They're the concept cars of the appliance industry: smart refrigerators, washers and dryers designed to use digital technology to improve efficiency. WSJ's Jason Bellini reports from CES on companies offering their visions for greener, and glitzier, appliances.

Katy Bachman, a travel agent who works from her house in Cape Coral, Fla., bought a home monitor last August and downloaded a meter application onto her computer desktop, which she checks throughout the day. Seeing that her consumption rose when she turned on her electric oven to heat up an individual pizza for lunch, she bought a toaster oven and now uses it or her microwave as much as possible. She also changed her pool pump to run less often and keeps her air-conditioning a few degrees warmer.

The result: a 20% reduction in her power consumption.

Instant Savings

These monitors "should be as widespread as TV sets," says Jon Wellinghoff, chairman of the Federal Energy Regulatory Commission. He purchased a monitor for his house last fall and estimates he has cut his home power consumption—and his electricity bill—3% to 5% so far.

Installations usually require an electrician, because the base unit connects to a home's circuit-breaker box and nearby wiring. But once they're up and running, the monitors are as easy to use as reading a meter.

Mr. Tassi, a former electrician, installed his system himself. He bought a TED 5000c, made by Energy Inc., Charleston, S.C. The $240 device (whose initials stand for The Energy Detective) measures how much electricity his house is using and how much it is costing him, minute by minute, and wirelessly transmits the data to a hand-held device.

After installing the system, Mr. Tassi started wandering around his house with the wireless reader. He turned on the dishwasher and the television and watched his power consumption increase. He also carried around a lamp and plugged it into different outlets.

In most outlets, the lamp used two cents of power an hour. But in three outlets, the lamp was sucking up six cents. Those outlets, it turns out, had loose wires. "It was a super nothing fix," says Mr. Tassi.

The Jackpot

But the real revelation was yet to come.

"I turned on the lights in the basement." Mr. Tassi recalls. "There were four fluorescent bulbs down there, and my electric usage went from 12 cents an hour to 86 cents an hour. I thought there was something wrong."

Mr. Tassi called Energy Inc.'s tech support, assuming he had installed his monitoring system incorrectly. After all, his energy auditors had praised him for using fluorescent bulbs that were more efficient than incandescent lighting.

But the bulbs weren't the problem. He took off the lighting fixture and noticed that the ballasts, tiny devices that limit currents in the circuits, were literally leaking electricity and had darkened the adjacent wood. For 20 years, this waste—and fire hazard—went undetected.

"I always assumed that the fluorescent bulbs couldn't be the problem," he says, but the faulty fixtures "were costing me $100 a month."

He replaced the fixtures and bulbs with LED lights. Now he says he can turn on a half-dozen LED lights and his hourly power consumption "doesn't even move a penny."

On the Lookout

Since September, Mr. Tassi has replaced most of his fluorescent and incandescent bulbs with LED lights, and he's grown more vigilant about unplugging devices that aren't in use. The hand-held display stays in the kitchen, where he keeps an eye on how much power he and his wife are using.

"I know my electricity usage should be about 10 cents an hour," he says. "When it gets up to 13 cents, I know there's something on somewhere that shouldn't be." He usually walks through his house looking for a lamp or computer that has been left on.

His most recent electricity bill was $85. And he's now thinking of lending the system to friends and neighbors.

He makes a point of showing off his latest bills to his neighbor across the street. Some months, he spends less then she does. But the real satisfaction is in knowing he is no longer wasting his money.

"One day it hit me," Mr. Tassi says. "Holy mackerel, I've been throwing money away for years."

Mr. Gold is a staff reporter in The Wall Street Journal's Dallas bureau. He can be reached at russell.gold@wsj.com.