THE GOOD old wood-burning stove. Just like grandpa used to do it. Cozy? Yes. Energy efficient? Yes. Safe? Well, if you installed it yourself, your stove could be a killer.

Do-it-yourselfs who have installed their own wood-buring stove - or plan to do so - could be running the risk of sending their home and all their belongings up in smoke. What's more, perhaps hundreds of Washington-area owners installed their stoves illegally. They are living with a fire hazard that never passed the mandatory inspection and could well leave them without fire insurance coverage should an accident happen.

These may seem like the words of a crazed killjoy in light of all the glowing praise the old-fashioned wood-burning stoves have received in recent years. Reports waxed effusive about their feul efficiency, about how warm and romantic they can be, and about how easy they are to install. But the fact is the stove boom of recent times has caught the marketplace and area governments unprepared to deal with it. (People were buying them faster than dealers could keep them in stock. The factories were backlogged with orders last year.)

For instance, the possible dangers of wood-burning stoves were turned aside because, buyers argued, local governments had stringent control over their installation. That just isn't so. A building permit is required to install the stoves, in all area jurisdictions, yet authorities estimate only half - perhaps only 20 percent - of people who buy a stove ever apply for a permit. Many can't receive a permit because the stove they bought was never underwritten by a nationally recognized testing organization, such as Underwriters Laboratories (UL). The Washington area jurisdictions require such approval on the stove before a building permit can be issued.

"I would suspect that better than 50 percent of these stoves are installed by the owner without a building permit," says Robert Goff, chief engineer for the Virginia State Fire Marshal's office. "And the building inspector never knows about it unless there's a problem."

Area stove dealers agree. "People don't like to go down and get a permit," says Jerry Taylor, part-owner of ACME Stove, which has a store in the District and one in Silver Spring. "There's so much red tape, people think they may have to speed a day (at the permit office)." But "that's not stopping people from putting them in," says Bruce Titus, salesman at Bromwell, which has stores in Bethesda, Rockville, Hyattsville, Falls Church and Alexandria. And, Taylor adds, "most people do the installation themselves."

There may be dozens of stove models on the market - especially the imported ones - that have never been tested and approved. At ACME Stove, for instance, there are between 30 and 40 brands to choose from. Fewer than a dozen of them. Taylor says, carry an underwriter's approval label. And while experts all agree that the key to stove is proper installation - and that stoves should be installed by someone who knows what he's doing - dealers who do installations carry many models they can't legally install.

"We can't put them in," says Titus, "we can't get a permit." Of all the models Bromwell carries, only one line-produced by the Washington Stove Co. - carries the UL seal.

For the past two years Kristia Associates of Portland, Maine, have been working with the UL to get approval for the highly regarded Jotul stoves they import from Norway. Virginia Roderick, vice president of the company, expressed Krista's concern.

"It is the responsibility of the company to inform the consumer of installation dangers," she says. "We want to keep the product safe for the consumer," UL has tested the Jotul models (distributed in the Washington area by ACME) and written a report, but Roderick did not know when or if approval would be given. "We feel very strongly about safety," Roderick says, "but it is the responsibility of the distributors and dealers to make sure the buyer has a permit, not Kristia." To show their concern, Kristia has organized the National Chimney Sweep Guild to inform dealers and distributors about consumer safety and installation.

Wood-burning stoves are a "high priority item" at the Consumer Product Safety Commission, says spokesman Mike Feinstein, because there have not been enough complaints. Some authorities worry that the rapidly growing stove market could bring a glut of unsafe, cheaply produced items. But many currently on the market, they add, are will constructed and not a hazard in themselves. They just haven't all been tested. What does worry officials is how people go about installing the stoves and large number that escape inspection and may be installed carelessly.

"We probably will have some problems this winter because there are so many people who read the installation directions only if all else fails," Goff says. "People are all doing their own Rube Goldberg thing," adds Taylor.

Data gathering systems are not yet sophisticated enough to show how many fires, deaths and damages have resulted from bad stoves and poor installation. But it is known that improper set-ups have caused fires and have killed people. ("Years ago," says William Canavan, assistant cheif investigator for the Maryland State Fire Marshal's office, "we used to see numerous fires in rural areas.") And the insurance industry, says Ronald W. Vinson, a vice president of the Insurance Information Institute, is just now reacting to the wood stove craze. There is no clear-cut policy on stoves per se, but owners done risk losing coverage, he says, if installation is not done properly because "the obligation of the (policy) holder is to not increase the hazard of fire with changes made under his control."

What are the dangers?

A wood-burning stove can get hot enought to set aflame any combustible material to which it gets close enough. Walls, carpets, wood floors, drapes - all can catch fire just being too near the stove. The same is true of the metal flues that carry the stove's exhaust out of the house. They get hot the same way as a car's exhaust pipe. For this reason, the stove and all connecting pipes and flues must maintain proper "clearance" from combustibles.

The guidelines for clearance have been developed by the National Fire Protection Association, and local building codes are largely a result of what the NFPA has set forth. They may vary in some jurisdictions, but in most cases the standard distance between stove and combustibles - walls and ceilings, for instance - is 36 inches. Also, the pipe connecting the stove to the flue must be as short as possible with at least 18 inches clearance. These distances can be reduced with the use of insulating materials, such as asbestos, sheet metal and fireproof brick.

Stoves also should not be placed directly on wood floors or carpeting. The stove bottom and combustibles must be separated by insulation.

The clearance requirements for pipes and flues call for a radial distance between them and combustibles, as when pipes pass through a wall. The pipe runs through a "thimble", a metal collar that fits into the wall.

Stoves can tap into existing chimneys, but they must not compete for use of the chimney with another applicance, such as a furnace. Where prefabricated chimneys are installed, they must be built to rise a certain height over the roof (and any other buildings within 10 feet), usually two feet.

Since some requirements do vary, and each home presents its own installation problems, the best idea is to show your plans to the local permit office, so possible hazards are caught before they are built in.

John Gird, an engineer in the University of Maryland's agricultural engineering departments, calls wood-burning stoves "the most dangerour form of heating ever built." Even NFPA officials will not go that far, but Gird has been researching stoves and their use for the last six months and cautions against do-it-yourself installation. "For the normal person to do it," Gird says, "will lead to disaster."

Gird advises would-be stove buyers to put some thought into what kind of stove will best suit their needs. People with children, for instance, should stay away from radiating stoves - often called "Franklin" stoves, after their inventor, Ben Franklin - because of the intense heat of the stoves' exteriors, against which children might bump or fall. Also the non-airtight stoves - ones that can be left open for a romantic evening watching the embers - can suck up children's night-gowns. For families, he says, the airtight circulating stove, which has a protective jacket, is a wiser choice.

Gird and dealers warn that some models are just plain bad. Taylor says his company "tries to stay away from" models imported from Taiwan because they've sometimes "known things to go wrong." Cast iron stoves, if they are not well constructed, have a tendency to crack. Steel stoves can wrap or burn through. Gird suggests using common sense: Check to be sure doors shut firmly and all have asbestos seals. Castings should look impressively solid, not disturbingly cheap. Kati Fauteck, representing Montgomery Ward in Chicago, which sells its own line of approved stoves, adds that parts should all come from the same manufacturer.

Wood-burners are not self-cleaners. A substance called creosote regularly collects on the inside of wood stoves, pipes and flues. "Nobody even knows what creosote is," says Gird. But if allowed to collect, it can one day cause a fire that "can rip the hell out of a chimney. It sounds like a tornado coming through the house." Some chimneys need cleaning as often as twice each heating season; all regularly used stoves should be cleaned at least once a year.

Local officials, such as Don Barrett, a plans examiner in Prince George's County, say that anyone with questions about stove safety and installation should call the local building inspector. Barrett and others recommend that potential buyers follow a few basic steps.

Make sure the stove and any parts carry the label of a recognized testing firm, such as UL, BOCA (Building Officials Conference of America) or ICBO (International Conference of Building Officials). A call to the building inspector will verify whether a particular stove qualifies for a permit.

Do not buy from someone who knows little more than you do. The dealer should be an expert in stoves and their installation.

Apply for a permit and, if a contractor is installing your stove, make sure he has a permit before he begins work.

Remember installations must conform exactly to manufacturer's specifications to pass inspection.

Make sure the stove is inspected after it is installed.

Notify your insurance company that you are installing a stove.

Most local governments offer some kind of literature on stove safety and installation. For information call: 779-3850 in Prince George's County; 468-4120 in Montgomery County; 558-2521 in Arlington; 750-6476 in Alexandria; 691-3361 in Fairfax, and 462-1762 in the District.