Tom Zeller Jr. / New York Times News Service

NOLANVILLE, Texas — Sgt. John Robertson II, an Army mechanic at nearby Fort Hood, is fuming about the so-called smart electric meter his local utility has installed on the side of his 1,800-square-foot home.

Like thousands of consumers with the new meters, Robertson suspects the device is not as smart as advertised.

In his case, he says it is inaccurately measuring his family’s power use and driving up his bills — some months by as much as 50 percent, to as high as $320 — since it was installed in December. This, he said, is despite his efforts to cut back on energy use.

“I’ve done two tours in Iraq, and when I come home I’m getting ripped off by my electric meter,” said Robertson, who with his wife, Kim, is raising four children on a tight budget.

Whether he and others are indeed getting ripped off is now a matter of national debate.

Over the past year, power companies have received plenty of complaints — and in some states been hit by class-action lawsuits — most of them from consumers saying the smart meters are overstating their electrical usage.

This is not the smooth rollout envisioned last year, when the Obama administration included money for utilities to install smart meters as part of a $3.4 billion injection of federal stimulus spending to modernize the nation’s power grid. By 2020, there could be as many as 65 million smart meters, by various makers, according to one estimate.

Using digital technology and computer networking, smart meters can transmit real-time data that is supposed to enable utilities to conserve electricity and better allocate power during parts of the day when overall demand is high. Utilities can also then vary the price for power, by time of day or time of year, based on when it is being used; some are already offering this option to customers.

Meanwhile, for customers with the right training and additional equipment, the meters can give households a much more detailed picture of the amount of electricity they are using, down to individual appliances. That, in theory, can help people reduce their electric bills and become greener citizens.

But because of faulty technology in some cases, and more often through general shortcomings in consumer education and customer-service support by many utilities, smart meters are leaving many customers dumbfounded.

In Maryland earlier this year, state regulators, aware of the discontent around the country, temporarily blocked a utility’s smart-meter proposal, citing inadequate planning and the potential cost to consumers.

In California, Michael Kelly, a lawyer handling a class-action suit against the state’s dominant utility, Pacific Gas and Electric, over billing disputes, said the problems probably had less to do with faulty devices and more to do with a hasty rollout. Old billing systems were merged with the new smart-meter technology, he said, too frequently resulting in erroneous charges.

“We’re just saying we want an evaluation done and that we want anyone who was overcharged to get their money back,” Kelly said.

A state-ordered analysis by the independent research firm Structure Consulting Group, released in September, agreed with the utility’s assertion that its new meters were accurate for the most part. The study also supported its conclusion that most of the complaints could be traced to a heat wave, changes in personal behavior or old meters that were actually malfunctioning and undercharging before the new ones were installed.

But the Structure report also said the utility had done a poor job of educating consumers and addressing their concerns. In basic terms, the smart digital meters are simply replacing the old analog meters, with their inscrutable dials and counters, found on the sides of homes all over America. But unlike those “dumb” devices, which are often read once a month by utility employees going house to house on foot, the digital meters can provide utilities with remote, real-time measurements of kilowatt-hours being used.

And consumers can benefit, smart-meter proponents say, because they can use a variety of add-on devices of their choosing, or online services, that allow them to view the meter’s real-time data too. The problem, some experts say, is that many smart-meter rollout programs have simply stuck the new boxes on the sides of homes, without fully explaining to consumers what smart meters are, how they work and what they can do to make the most of them.

“The smart meter itself is just a relatively simple, computerized tool that, in the end, will work just fine,” said Richard Caperton, a policy analyst and energy and climate expert with the Center for American Progress, a liberal policy group in Washington. “But the customer relationship is a delicate thing, and it needs to handled with that in mind.”