There is something comforting about a fireplace. Besides being elegant and warm, they are romantic. And it is what Americans want in their homes.

Sixty-two percent of the new single-family houses built in 1987 have fireplaces, according to the U.S. Census Bureau. In a survey in the October issue of Remodeling magazine, the addition of an energy-efficient fireplace was one of the most popular remodeling options, says Donna Larcen of the Hartford Courant. The magazine surveyed 18 U.S. cities; in the Boston area, for example, a fireplace addition resulted in a 155 percent return at resale time.What many buyers are looking for is a combination of open flame and energy efficiency.

But the traditional masonry fireplace only radiates about 15 percent of its potential heat into the house. The rest - 85 cents out of every energy dollar spent - goes up the chimney. And as the fire dies, even more heat is sucked up the flue and the efficiency drops to about 5 percent. Even a poorly tuned furnace will perform more efficiently than a fireplace.

Various gadgets - glass doors, and fans and pipes to blow heated air back into the room - make traditional fireplaces marginally more efficient. Or an airtight, boxy wood stove, said to burn all night at about 60 percent efficiency, can be installed.

Wood stove shoppers should be aware of new federal pollution regulations. Air pollution problems and heavy use of wood stoves in Colorado and Oregon have led to federal standards. (The regulations apply to wood stoves only, not coal stoves, gas stoves or fireplaces.) Look for a tag that says the stove meets federal Environmental Protection Agency regulations.

Another trend is the use of gas as an alternative to wood in the more efficient stoves. There also are a number of dramatically designed fireplaces that incorporate some of the efficiency of wood stoves with the aesthetic appeal of an open fireplace.

But the bottom line is: Don't expect your fireplace or wood stove to be your main heating source. During the OPEC oil embargoes of the '70s, many people thought they could be used that way, but that attitude has changed.

There are other reasons for wanting a fireplace. If people were interested only in energy efficiency, they would live in houses without windows. Aesthetics can triumph over rationality.