DETROIT — Early adopters of electric vehicles have to dig deep into their wallets to make the purchase, but some are reaping unexpected savings on their insurance bills.

Insurance premiums vary widely based on driving history and local crime and vehicle theft rates, but experts said owners of vehicles such as the Chevrolet Volt and Nissan Leaf can generally expect a lower insurance premium.

“When you look at electric vehicle owners, you probably have a pretty careful bunch there,” said Jack Nerad, executive editorial editor and market analyst at Kelley Blue Book. “They’re probably pretty mature, and they’re not the young 20-something male who gets into the most fights and has the most car accidents.”

Although electric vehicles are likely to remain a niche segment of the auto industry for several years, insurers are starting to compete for electric-vehicle policies.

Hartford Insurance announced in April that it would start offering a 5 percent discount to electric-vehicle owners throughout the U.S. by the end of the year. The company described the offer as part of its commitment to encouraging environmental sustainability.

But experts said the insurer wouldn’t make the offer without believing that it is a smart financial bet.

“You can count on that,” said David Cole, chairman emeritus of the Ann Arbor, Mich.-based Center for Automotive Research. “Right now it’s almost too early in the game to make that judgment, but they believe it, otherwise they wouldn’t be making that pitch.”

Rick Lipinskas, an Albany, N.Y., resident who bought a Volt in March 2011, said he’s paying about $1,000 per year for “more-than-minimum coverage plus collision and uninsured driver coverage” through New York Central Mutual.

“From talking with other Volt owners, we seem to be less hurried while driving,” Lipinskas said in an email. “I tend to set the cruise control at the speed limit instead of 5 mph above as I did in my previous car, a 2007 Honda CR-V.”

The average insurance policy for a 2012 Volt owner who drives 15,000 miles annually is about $1,452 per year for the first five years, according to estimates from auto research website Edmunds.com. That compares with about $2,024 for a conventional-engine 2012 Cadillac CTS, for example.

The Volt, which uses a battery to travel up to 35 miles on electricity before a small gasoline motor kicks in, starts at about $39,000, while the CTS starts at about $36,000.

The average insurance policy for a 2012 Leaf owner is about $1,513 per year, while the average for a conventional-engine 2012 Nissan Maxima, for example, is $1,801, according to Edmunds. The pure-electric Leaf starts above $35,000, while the Maxima starts at about $32,400.

To be sure, some electric vehicle owners are not reporting a discount. Phoenix-area resident Paul Cummings said his insurance premiums with State Farm rose $17 per month after he switched from a $44,000 Ford F-150 to a Volt.

Brittany Senary, a spokeswoman for insurer Progressive, said some drivers who switch to an electric vehicle might notice an uptick in their insurance premiums if the vehicle is more expensive than their previous ride.

“Because newer vehicles with more expensive technology and parts generally cost more to fix than older, less-complex cars, they’re generally more expensive to insure,” Senary said in an email. “We don’t currently offer EV discounts because we cannot justify them based on our claims data.”

Nerad said some insurers may be unsure how to price their policies because of the expensive battery packs that are integrated into electric vehicles. Those batteries are rarely damaged in accidents because they’re enclosed in protective cages.

“What I’ve learned about insurance through the years is a lot of times you’re not looking at how safe the vehicle is but how safe the driver is,” Nerad said.

Doug Neal, executive director of the University of Michigan College of Engineering’s Center for Entrepreneurship, got a first-hand look at the electric-vehicle insurance business when he crashed his Chevy Volt a few months ago.

Another driver turned in front of Neal’s Volt in downtown Ann Arbor and slammed into his front bumper, causing minor damage.

“The only complexity was I couldn’t just take it to any repair shop,” he said. “I had it taken to one that knew how to work on an electric car. But they have a network of those.”

Neal said that when emergency responders arrived on the scene of his accident, they weren’t too worried about insurance.

“When people showed up — the police officer, the tow truck driver — they were all so excited about the car,” he said.