Fireplaces: Kill The Chill

I have a standard fireplace in my house, but I would like to add a wood-burning fireplace or insert for more heat and the ambiance. My existing fireplace seems to chill the house. What should I look for?—Paul M.

Though it may seem contradictory, an open masonry fireplace can cool your house and increase overall heating costs. The fireplace draws heated indoor air up the chimney and out of the house.

A resulting vacuum draws in cold outdoor air through windows, doors, and any gaps. You may feel comfortable in front of the fireplace, but your furnace runs like crazy trying to keep the rest of the house warm.

Although I do not recommend using an open fireplace during cold weather, if you really do like the ambiance of a fire, close all the doors to that room, open a window, and turn the furnace thermostat down. You will still lose some heated air up the chimney from the rest of the house, but most of the air should be drawn from the open window. The loss is not as severe during mild weather because outdoor air is not as cold.

Every efficient wood-burning fireplace or insert will have tight-sealing glass doors between the room and the chimney to block the loss of already heated room air.

Consider the options
When buying or upgrading a fireplace, you’re faced with several choices. Initially you must decide between a zero-clearance or masonry fireplace. If your old fireplace is large, you may be able to fit a new unit inside. If you plan to install a fireplace somewhere else, installing a zero-clearance model is easiest. It often uses a double-walled design with insulation so it can be safely placed against wood wall studs.

A heat-circulating fireplace provides the best efficiency and most heated air output. Many of these operate without a fan and rely on the natural flow of room air around a superhot firebox.

If you want more heat output and better control of the flow of heated air, install an optional blower kit with a thermostat and variable-speed control.

Airtight fireplace inserts provide the longest burn time on a load of firewood and the greatest maximum heat output. They are not as stylish as a fireplace, but they provide much better control over the heat output and combustion air used.

Save More
Fire up a tax credit
Burning firewood to heat your home may qualify for a federal tax credit. The credit applies to any biomass heating appliance placed in service during 2009 and 2010, and is equivalent to 30 percent of the cost, including installation, up to $1,500. To qualify, the appliance must have an efficiency rating of 75 percent or greater. For details, check www.energystar.gov/taxcredits.