Sylphon Regitherm Thermostat

The Fulton Company of Knoxville, Tennessee manufactured this Sylphon Regitherm thermostat around 1910. The thermostat could be set between 60 and 80 degrees. The Regitherm operated by the expansion and contraction of the metal bellows seen at the far left of the object, changing the temperature on the thermostat varied the liquid level inside the bellows. Once the bellows contracted to a certain level, the liquid exerted a pressure on the mechanism that opened the damper system on the furnace, increasing the heat.
The ubiquity of thermostats in 21st century homes shrouds the decades of innovation, industrial design, and engineering that went into making them an everyday object in almost every home. In the early 20th century, a majority of American households still heated their homes with manually operated furnaces that required a trip down to the basement and stoking the coal fired furnace. Albert Butz’s “damper-flapper” system was patented in 1886 and allowed user to set the thermostat to a certain temperature which would open a damper to the furnace, increasing the fire and heating the house. Progressive innovations allowed for the thermostats to use gas lines, incorporate electricity, turn on at a set time, include heating and cooling in one mechanism, and even connect to the internet.
Currently not on view
Object Name
overall: 6 1/4 in x 7 3/4 in x 6 1/2 in; 15.875 cm x 19.685 cm x 16.51 cm
overall: 6 in x 7 3/8 in x 5 3/4 in; 15.24 cm x 18.7325 cm x 14.605 cm
ID Number
accession number
catalog number
Domestic Furnishings
Engineering, Building, and Architecture
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Work and Industry: Mechanical and Civil Engineering
Data Source
National Museum of American History, Kenneth E. Behring Center

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