Rumford Fireplace: Lord of the Flues
When it came time to build a fireplace, Roger Wells told his mason that he wanted a Rumford — the single best fireplace design to come along in the last 200-plus years. Count Rumford, born Benjamin Thompson in 1753 in Woburn, Massachusetts, was a physicist and genius inventor, a Tory who fled Boston with British troops in 1776 (after he was accused of informing on the Minutemen).
In London, Thompson experimented with gunpowder and other explosives, developed new methods of signaling at sea, and published a treatise on how to build a fireplace that would heat but never smoke. King George III was so impressed with Thompson that he knighted him. Later, Sir Benjamin spent 11 years in Bavaria in various posts, including minister of war, and for this service was made a count of the Holy Roman Empire in 1791. Thompson took the name “Rumford” from his wife’s birthplace, now Concord, New Hampshire. The Rumford remains one of the most efficient fireplaces you can build.
Read Tim Clark’s review of a new biography of Count Rumford.
Detail, from Robert Kaldenbach
The well-tempered Rumford fireplace features a throat that is a bare four inches from front to back, running the full width of the chimney, all the better to keep heat down below and create a strong draft above. At the throat, where the fireplace becomes the chimney, a shelf (X-Z) has been built so that rising smoke meets and mixes with fresh air entering the chimney from above. A Rumford fireplace locates the fire toward the front, directly beneath the chimney, so smoke rises vertically to the throat without turbulence. Rumford narrowed the fireback, which allowed the sidewalls to be slanted. The fireback width (A-B) is the same as the fireplace depth(B-C), creating a square floor.