The Count Rumford Fireplace

By Lisa Hassler on November 14, 2017

When we first viewed the c. 1827 home that we would ultimately purchase, we were thrilled with the four fireplaces.  The home had once been a double dwelling house for the workers at the Boston and Sandwich Glass Company.  Each side of the house has a kitchen fireplace, with a beehive oven, and a parlor fireplace.  And each fireplace has the tell tale angled walls of a Rumford style fireplace.

Sir Benjamin Thompson (Count Rumford)
birthplace in Woburn, MA

Count Rumford, born Sir Benjamin Thompson in 1753, was a soldier, statesman, inventor, scientist and humanitarian.  He was born in Woburn, MA and studied at Harvard.  Being a loyalist, he left for England in 1776 where he was later made a fellow of the Royal Society.  His title was bestowed in 1790 when he was made count of the Holy Roman Empire.  Interestingly, “Rumford” came from the place where he lived in NH at age 19 (now Concord).

A fireplace in the Benjamin Thompson house

His name lives on through his contributions to science, and in particular, his advancements to heating.
In 1798 and 1799, Count Rumford wrote a series of 3 essays describing the ills of the common form of construction of a fireplace and the remedy to save fuel and increase comfort:

Chimney Fireplaces, with proposals for improving them to save fuel; to render dwelling houses more comfortable, and salubrious, and effectually to prevent chimneys from smoking.

p. 547

Shows the common construction of a fireplace prior to alteration

p. 549

Shows the same fireplace after Count Rumford’s suggested improvements

Rumford’s suggested improvements caught on like wildfire (pun intended)

Fireplace in the Cobb House Museum, Brewster
Kitchen fireplace, home in Yarmouth Port
Monticello, South Square Room, facing East

According to, Thomas Jefferson’s Monticello has 8 Rumford style fireplaces.
Jefferson wrote to his friend, Wilson Cary Nicholas regarding the dimensions of his Rumford fireplaces:

Mr. P. Carr informed me two days ago that you wished for the dimensions of the Rumford fireplaces.  I therefore avail myself of the first post to send them.  I state them as I have used them myself, with great satisfaction, the back one half of the opening.  Count Rumford makes the back but one third of the opening, this was to accommodate them to coal; but it renders them impracticable for wood.  My larger fireplaces I make 2 f in the back & 4 f in front; those for bed-rooms 19 1/2 i in back & 3 f - 3 i in front.  The opening of the former 3 f - 3 i or 3 f - 6 i high, the latter 3 f high

Which brings me back to my fireplaces – none of which are currently working.  We are having them parged inside and re-pointed where needed.  Our mason tells us that the fireplaces have great draw – Yay Rumford!

MACRIS Inventory formMiddlesex Canal Society Monticello