Three years ago Leslie Pearlman spent $1,500 for a combination burglar-fire alarm sytem for her two-story brick house.

Within the first year, the window latches that trip the alarm began to fall off "almost every time someone opened a window," Pearlman recalled. Later, when the Pearlmans tested the fire-alarm system, they found that two of the sprinkler heads hadn't even been wired.

"He (the installer) didn't know what he was doing," said Pearlman, who has been fighting the company in small claims court.

The Pearlmans' problem is one confronting many consumers entering the growing home security market. Unable to install or maintain their own systems, they often are dependent on an industry which some say is suffering from a high turnover of companies, poor installers and a few high-pressure salesmen.

"People use the companies like a crutch," said Thomas F. Smith, president of Security, Inc., a Washington-based alarm firm. "After a while, if they don't have a crutch around, they're lost."

Manufacturer sales of home security systems rose from $71 million in 1975 to $110 million last year. That number -- fanned by concern over the more than 2 million reported residential burglaries each year -- is expected to jump to more than $203 million by 1985, according to estimates by Frost & Sullivan, Inc., a New York marketing research firm.

Even so, th residential alarm market still takes in less than 10 percent of the gross revenues of the commercial-industrial-residential market. And less than 2 percent of U.S. homes are equipped with burglar alarms, Frost & Sullivan statistics show.

Feeding the small but growing home security market is a group of approximately 600 burglar alarm manufacturers and some 6,000 companies specializing in installing, servicing and monitoring the systems.

But the annual turnover rate of individual businesses in the industry has been high -- more than 30 percent in some urban areas, industry people estimate -- forcing consumers often to seek out new companies to maintain their systems.

Allan Reynolds, president of the National Burglar and Fire Alarm Association, attributes much of the high turnover to entrepreneurs expecting to make a fast buck. But they find out fortunes are not so easily made.

"You don't need a lot of investment to start in the business," Reynolds said. "But these people learn that the business is a lot more complex than they thought at first. It is a little different than selling ice cream cones."

Similarly, a few industry people complain about colleagues' sales tactics.

Stories are told of people who use a crowbar as part of their sales presentation. They wield it in the air, the story goes, telling the customer: "This is the burglar's key to your front door."

Other firms use police crime reports as a source list for new customers. In the Washington's suburban Montgomery County, for instance, county police say representatives from several companies check crime sheets almost daily to pinpoint where the latest burglaries have occurred.

Salesmen then call the people in the area to urge them to buy an alarm system.

Yet, Pittsburgh security industry consultant Norman Eisinstat argues that more aggressive tactics are needed to reach the still untapped market.

"Why shouldn't you use scare tactics -- it is scary," he adds.

When choosing an alarm company, keep these tips in mind:

Find out how long the company has been in business. It usually takes a few years to become firmly established, industry people say.

Ask a company for a list of references or satisfied customers and check them out.

See if the company is Universal Laboratories-approved or is a member of the National Burglar and Fire Alarm Association. A number of regional and state alarm industry groups also have been formed, which give out consumer advice and handle grievances.

Check to see if the company will install -- and service -- your system. Some firms refuse to repair a system installed by another company.

Check with the local Better Business Bureau council or the alarm association about a company's reputation.