Do burn soft woods like fir, pine, and cedar, which ignite easily and burn rapidly, so they are ideal to use as kindling. For staying power, use harder woods, such as oak, maple, and hickory. Freshly cut wood contains a lot of moisture, pitch, and resin and tends to produce creosote, a flammable substance that attaches to chimney walls. So buy seasoned wood, or season your own by keeping it off the ground under a rainproof tarp for at least six months, says the Environmental Protection Agency. (Hit a log against another; if it makes a hollow sound, it's ready.)
Never burn chemically treated or painted wood, foil, plastic, or other garbage, all of which produce noxious and sometimes toxic fumes. Other no-nos:
Christmas trees. "The unseasoned wood and dry needles make them powder kegs, highly combustible," says Roy Marshall, director of the Residential Fire Safety Institute, a national advocacy group.
Gift wrap, and other chemically treated paper―lit fragments can ignite creosote on chimney walls or land on your roof, says Ashley Eldridge, education director of the nonprofit Chimney Safety Institute of America.
2 of 4Beatriz da Costa
Does a Fire Help Heat a Room or Take Heat Away?
As much as you love it, "your fireplace can be one of your most inefficient heat sources," says Gary R. Schmitz, a public-affairs officer at the National Renewable Energy Laboratory, part of the U.S. Department of Energy (DOE). Here's why: Fire needs oxygen to burn, so it draws warm air in from the room at a rate of up to 300 cubic feet per minute. Then, "as the fire burns, it heats the air around it―and heat rises," Marshall explains. As the warm air escapes through the chimney, cooler air from outside rushes in to fill the void. The net result, says Marshall: "You'll feel warmth from the fire if you are sitting close by, but you're siphoning more heat out of the room than you're creating."
A number of accessories claim to improve the equation, but the only ones that make a real difference, according to the DOE, are high-efficiency fireplace inserts. Professionally installed (and pricey), these are typically cast-iron or steel chambers that sit inside the hearth and enclose logs behind glass doors. They work by controlling the flow of air to the fire; many also have blowers to direct heat into the room.
3 of 4Beatriz da Costa
How Often Should Fireplaces and Chimneys Be Cleaned?
To avoid chimney fires, hire a professional once a year to inspect yours for cracks, blockages, and creosote buildup and to give it a good cleaning. (To find a certified sweep in your area, go to the Chimney Safety Institute of America's website, csia.org.) During the rest of the year:
Shovel or sweep out ash from your fireplace after every fire for safety: Ash acts as an insulator, so any hot coals buried deep within can stay hot for days. Also, accumulated hot ashes will wear out the grate.
Keep an eye out for visible damage. "If you see any cracks around the hearth and flooring or gaps between firebricks, have them inspected right away by a chimney sweep," advises Michael Litchfield, author of Renovation ($40, amazon.com). "A spark could get into the breach and cause a fire."
If you don't already have a spark arrester, also called a chimney cap, consider asking the sweep to install one, says Eldridge. Generally costing from $100 to $300, it will prevent sparks from escaping the chimney and landing on your roof or someone else's, while also keeping debris and critters from getting in.
4 of 4Beatriz da Costa
What Are the Differences Between Gas and Wood-Burning Fireplaces?
You're not going to get the lovely snap, scent, or blazing heat of a wood fire from a gas fireplace―or that whole outdoorsy thing of toting in the logs and getting the kindling going. What you will get is convenience. With the flick of a switch, the propane or natural-gas burner beneath the faux logs (usually made of ceramic or concrete) creates a constant flame that curls around them to mimic a bona fide wood fire. Other benefits of gas fireplaces:
Gas fireplaces are generally more efficient than wood-burning models and give off more heat, says Marshall.
There's zero cleanup.
They're gaining in popularity in U.S. homes―they accounted for two-thirds of the 2.8 million fireplaces sold last year, according to the Hearth, Patio and Barbecue Association, a national trade organization.
Gas fireplaces can be vented (with a chimney or a vent to the outside) or unvented (chimneyless), but you may want to stick with vented models. One study suggests that unvented fireplaces contribute significantly to indoor air pollution―a particular concern for those people suffering from respiratory diseases, such as asthma.