Rumford fireplaces, masonry heaters superior, mason says

January 11, 1999|By KERRY LYNN FRALEY

Hagerstown mason David L. Geller has two reasons for preferring masonry heaters and Rumford fireplaces to traditional fireplaces.

Backed by a stack of articles and books covering his dining room table, Geller claims they're both more efficient heat sources and cleaner burning.

A centrally located masonry heater - which thrives on small pieces of wood that would burn too fast for a fireplace - can be used as a primary heat source because it will continue to radiate heat long after the fire burns out, he said.

They take up a little more space than a regular fireplace, but that's because a lot more is going on inside them, Geller said.


Instead of a single burning action, like you have with a fireplace, the fuel burns twice, first as a solid in the firebox, then as a gas in a secondary chamber, he said.

That dual burning process yields 80 percent to 90 percent of the fuel's energy potential, compared with about 30 percent yielded from burning just the solids, Geller said.

Also, before going up and out of the home through a flue, the remaining hot gases are channeled within the masonry, heating it so it radiates warmth into the home even after the fire stops burning, he said.

The design - which dates back more than 150 years in Scandinavia - uses the same concept that ancient peoples used when they plunged rocks taken from a burning campfire into water to heat it, Geller said.

He said he plans to sacrifice his centrally located dining room to build a masonry heater capable of heating all of the home except for the basement, where he plans to build a Rumford fireplace.

Rumford fireplaces have been around since the 1790s, when an American-born British loyalist named Benjamin Thompson - Count of Rumford - applied his research in heating to improve on the traditional fireplace design.

The design of a Rumford fireplace, which features a shallower back and more steeply angled sides than in a traditional design, maximizes radiant heat, Geller said.

Another difference is in its curved "throat," which shoots combustion gases and air from the firebox up into the smoke chamber in separate streams, rather than creating the turbulent mix that cools the gases and promotes creosote formation in the chimney, he said.

While easier and less expensive to build in new homes, both masonry heaters and Rumford fireplaces can be installed in an existing home, Geller said.

With a little demolition, a traditional fireplace can be transformed into a Rumford fireplace, he said.

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