Energy Q&A.

Warm Front

The Energy Efficiency Of Fireplaces Is A Burning Issue

November 03, 2000|By Jim Sulski, Special to the Tribune.

Q--What can you tell me about what's known as a masonry fireplace? I've read that most fireplaces, including those that burn natural gas instead of wood, are inefficient energy-wise. Somewhere I read that if you're going to have a fireplace, a masonry fireplace is the way to go. Are they that much more energy efficient than a regular fireplace?

A--Let's start with a little background on fireplaces in general. Yes, most fireplaces are inefficient energy-wise, meaning you lose more heat (and the dollars it takes to generate that heat with your furnace or boiler) than you gain from the fireplace.

In fact, most fireplaces, both wood-burning and natural gas-burning, are there for aesthetic values, which means they produce a nice fire to look at.

Yes, standing next to a fireplace will make you feel warm from the radiant heat, but there's a lot more heat, including the heat from the rest of your house, going up the chimney.

Because of the way it is constructed, a masonry fireplace reduces some of the energy loss and is used in places such as Europe as a heating device. A masonry fireplace is also the cleanest way to burn firewood, a plus for the environment over a traditional wood-burning fireplace.

Masonry fireplaces are also known as masonry heaters because of their efficiency. They are also called Finnish, Russian and Siberian fireplaces.

A masonry fireplace is basically a large brick and/or stone fireplace that uses that brick or stone to capture heat from a fire and then slowly disperse it back into a home later.

The downside to a masonry fireplace is you don't get the aesthetics of a traditional fireplace. Because the fire is contained inside an airtight firebox, it's not a roaring, crackling fire or a fire that you can roast marshmallows on.

In addition to the firebox, a masonry fireplace consists of a masonry mass (the stone or brick) and smoke conduits that run through that mass.

When a wood fire is burning in a masonry fireplace, it burns very hot and very quickly. The hot gases produced from the fire are channeled through the conduits, warming the thermal mass from the inside out. That mass then warms the room.

As a result, a masonry fireplace works more efficiently when it's in the center of a room--that allows the thermal mass to best distribute the heat.

Some masonry fireplaces burn so efficiently and so warm that they have a built-in cooking oven and can be used to make bread or pizza.

Because of their efficiency, masonry fireplaces are more costly to construct than a typical fireplace. You also have to find a qualified craftsman to build one. For more information on masonry fireplaces, check out the Masonry Heater Association of North America's Web site at

Also, check out the Energy Efficiency and Renewable Energy Network, or EREN, Web site at, which is run by the U.S. Department of Energy.

