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Fireplaces, Stoves and Energy

House Doctor | Gary Dymski

October 5, 2000

IF YOU'RE thinking about using your fireplace to help heat your home and lower your fuel bills this winter, there are some good reasons to think again.

Using your fireplace more often actually could increase the cost of heating your home. And with the price of natural gas and home heating oil expected to be up by as much as 40 percent, it's important that you make wise supplemental home heating decisions.

Heating and air conditioning make up about 44 percent of a household's energy use, says the U.S. Department of Energy, with heating making up nearly two-thirds of that use in colder climates.

Unless it is equipped with an airtight insert that's designed to provide you with high-efficiency heat, that cozy fireplace actually is pushing warm air out of the house when it is filled with a crackling fire. The immediate area around the fireplace might be toasty, but outlying rooms will be ice cold. The reason is that a fire needs oxygen to burn, and the nearest source of oxygen is the interior of the house. As the fire burns, it creates a vacuum; fresh air is sucked from inside the house to the fire and out the chimney. The air shooting up the chimney is replaced by cold air that comes from outside the house; it enters though the smallest of openings, like cracks in door and window seals.

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Eliminating the vacuum and using a wood-burning device, like an efficient fireplace or stove, for heat, can be pricey-from about $ 2,000 for insert purchases, including installation, and a little less for a wood-burning stove. But if your goal is to reduce your dependency on natural gas and home-heating oil over the long haul, it's probably a good way to go. And for those who still want a fireplace for show, there are gas-burning units that don't need chimneys. Both wood- and gas-fired fireplace inserts and stoves burn at 80 percent efficiency or higher.

"We've had a renewed interest in fireplaces and wood-burning stoves lately because of the expected increase in home heating oil," says Steve Turrigiano, owner of All-Seasons Fireplace and Stone Gallery in Middle Island. "People are concerned with efficiency, and they want to know how long it will take to recoup their investment ...I don't think you'll be able to get it all back in one year, but two years? With the price of home-heating oil around $ 2.50 a gallon, I'd say it's possible."

For years, most of Glenn Richter's customers sought out a fireplace for the ambience. "Especially in the high-end homes," says Richter, general manager of Big Apple Barbecue & Fireplace Center in Whitestone, Queens. "And wood-burning stoves were all but dead, but people are asking about them now."

To get both high-efficient heat and the warm look of a fireplace or old-fashioned stove, consumers need to decide first on whether to use wood or gas as fuel.

Direct-vent gas burners allow for installation of fireplaces and stoves virtually anywhere. A double-lined pipe is vented to the exterior, with one layer of the pipe providing intake air, the other an exhaust route. (If you're going to burn gas, remember you're not going to lower your heating bills. When you use the fireplace or stove for heat, it will burn efficiently and provide a cozy atmosphere.)

"Homeowners who never thought they could have a fireplace are now able to have them," Richter says.

For those who favor burning wood, the placement of an insert or stove is a bit more restricted. Wood-fired inserts and stoves need their own chimney. In masonry fireplaces, the insert is fitted into the existing opening, and a vent pipe is run through the chimney. For stoves, which start from about $ 650, a steel chimney is created by running an exhaust pipe to the roof.

In both inserts and stoves, an airtight seal is created and the wood burns intensely and for long periods. A couple of logs that burn in an hour in a traditional fireplace might take three times longer to burn in a fireplace with an insert. The oxygen for the fire is supplied by room air, however, the vacuum effect is eliminated. Inserts and stoves feature double walls, with the interior box holding the fire and venting to the chimney. The hot air between the boxes is what is used to heat the room, and a fan circulates the air between the walls back into the room.

Blowers turn radiant heat into "convection heat." If you're wondering how much heat is provided, consider that some of the smallest inserts and stoves equipped with blowers can produce 24,000 BTUs in an hour.

Both wood- and gas-fired units also burn cleaner than they used to. Over the past several years, the Environmental Protection Agency has set wood stove emission standards. (For more information on wood burning, write the EPA's Wood Heater Program, U.S. Environmental Protection Agency, Manufacturing, Energy, and Transportation Division (2223A), OECA/OC/METD, 401 M St., SW, Washington, D.C. 20460.) Most units can be purchased with catalytic combusters (similar to catalytic coverters on automobiles), which cause exhaust gases to ignite. The result is a cleaner, more efficient burn; the wood burns once and the exhaust gases burn again. For efficiency and comfort, make sure you buy a unit with both a blower and a catalytic combuster.

These inserts and stoves can be installed by an experienced do-it-yourselfer but typically are better left to the professional. "They're pretty heavy, first of all, so it's not a one-man job," Turrigiano says. "A smaller insert weighs about 275 pounds, the larger ones about 475 pounds. In addition, you need a lot of patience to run the pipe." Installation usually runs between $ 375 and $ 475.