Minneapolis-Honeywell Chronotherm Thermostat, 1935

This is a Chronotherm Model T105 thermostat that was manufactured by the Minneapolis-Honeywell Company of Minneapolis, Minnesota around 1935. The T105 Chronotherm was one of Minneapolis-Honeywell’s more expensive thermostat offerings in 1935, selling for $41.00. This Chronotherm used Honeywell’s patented “Heat Acceleration” feature to anticipate a drop in temperature and kick on the furnace earlier to level the heat and avoid the “cold 70°.” The thermostat would warm itself up two degrees so that by the time it reached the pre-set thermostat temperature it would know to turn on and re-heat the room.
The ubiquity of thermostats in 21st century homes shrouds the decades of innovation, industrial design, and engineering that went into making them an everyday item. 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. Refilling the furnace with coal was still necessary. Progressive innovations allowed for the thermostats to use gas lines, automate coal fueling, 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
overall: 8 in x 3 1/8 in x 2 3/4 in; 20.32 cm x 7.9375 cm x 6.985 cm
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Work and Industry: Mechanical and Civil Engineering
Domestic Furnishings
Engineering, Building, and Architecture
Data Source
National Museum of American History


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