Worse yet, they rob heated air from your home for combustion, which means that your furnace might actually work harder to heat rooms not warmed by the fireplace.

Choosing and buying a prefab fireplace. When shopping for a prefabricated unit, you must first decide if you want a built-in or freestanding unit. Built-ins, which can be fairly difficult to install, look like traditional fireplaces. Freestanding units come in many shapes, sizes, colors, and styles, and most have a contemporary look.

Both types vent through insulated metal chimneys that you can run up through walls, ceilings, and roofs. Not only are these metal flues easy to assemble, but some also feature a "positive draft" that guarantees a smokeless fire. You can veneer these prefabricated units with masonry or, in some cases, build conventional wood-framed walls around them. Freestanding fireplaces usually occupy less space and offer more design flexibility. Just set one in place and hook up a chimney.

Selecting energy savers. If you plan to
use your new fireplace as a source of
heat, shop for efficiency. Heat-circulating
fireplaces include built-in ducting to direct
warmed air back into the room or into
adjacent rooms. Add electric blowers and
you have a wood-burning fireplace.

Fresh-air-feed fireplaces don't rob heat
from your home while they burn. Instead,
they pull in combustion air from outside via
a dampered duct. They also distribute a
lot of heat. Both heat-circulating and
fresh-air-feed fireplaces create convection
currents that supplement the firebox's
radiant heat.

Installing a freestanding unit.
Lightweight construction and easily
assembled components make installing a
freestanding fireplace a feasible project for any do-it-yourselfer willing to tackle the tricky task of getting a chimney through the roof. If the fireplace requires a non-combustible base, construct this first. You can pour a thin concrete slab, motar bricks or tiles together, or fill a wooden, tin-bottomed frame with loose gravel. Be sure to check building codes before you buy any prefabricated chimney--not all makes are widely approved. You may need a building permit, too.

Thinking about treating yourself to the warmth and crackling aroma of a new fireplace? If so, you have lots of choices and decisions to make. Unless you are building a new home, you will probably rule out an all-masonry type fireplace right away. Pouring deep footings or making structural alterations is too expensive compared to the cost of installing prefabricated units that come in kits.

What's more, many prefabricated units burn more efficiently than all-masonry fireplaces. Some fireplaces that were built before energy became a major expense lose as much as 90% of their heat output up the chimney.