The truth is that conventional fireplaces send more heat up the chimney than they provide to your home. But the good news is that exciting new technologies now add energy-efficiency to the romantic tradition of the hearth.

Yet, purists needn't fear that the wonderful looks of their hearths will be compromised. The shifting shapes and colors of the fire will be as fascinating as ever, and the instant solace the fireplace offers after cold commutes and shopping trips will remain unabated.

"Many inserts include such aesthetic features as decorative tile, cast iron or enameled fronts, glass bays and brass trim," notes Sura Malaga of SRM Designs, Holmdel, New Jersey. "They won't embarrass even the most elegant rooms."

Homeowner Barbara Boon became a fan of inserts during a severe winter a couple of years ago. "We were hit by a power outage at a time of plummeting temperatures," she recalls. "With our heating system out of commission, we kept our wood-burning fireplace going, and thanks to the insert we were able to keep the entire first floor toasty and the second floor warm enough to keep pipes from freezing and bursting."

Fireplace inserts are heating units that fit into existing fireplaces and can burn wood, gas or wood pellets. They can generate more than 70,000 BTUs per hour and can warm up to 1900 sq. ft. of space.

Some models extend onto the hearth while others stay flush with the front of the fireplace. Most have tight-fitting glass or metal doors and built-in circulation features. The most efficient models supply combustion air from outside the house, and virtually all inserts are controlled-draft units with manually or thermostatically controlled air inlets. Some units are also available with catalytic converters for improved efficiency.

Glass doors, heat exchangers, dampers and flue sealers can also up the energy efficiency of an existing fireplace, but don't expect too much. According to the Department of Energy, those devices combined could only improve efficiency by some 10%.

Another interesting option is the new fireplaces that don't require masonry chimneys, for they can be installed easily and safely in most any room. They are simply vented through an outside wall, and they are available as wall units, islands, peninsulas and two-sided models that let you enjoy the fire from adjoining rooms. They may burn wood, gas or propane.

Malaga calls these fireplaces "a romantic's dream scenario." "This is the way to get the fireplace you always wanted in the bath," she says. "Or in the kitchen. Or bedroom"

There is no question that fireplaces are terrific and getting better all the time, but your mom was right on the money when she warned you not to play with fire. Safety is all-important, so before changing a fireplace or adding a new one, consult an architect or fireplace specialist. Also check local codes with your town's building department