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The Honeywell Round Thermostat

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Black and white photograph of Honeywell Round thermostats ready for final checkout and packaging at a factory in Golden Valley, c.1955.

Honeywell Round thermostats ready for final checkout and packaging at a factory in Golden Valley, c.1955.

The world's most iconic home thermostat was created in Minneapolis. The Round, designed by engineer Carl Kronmiller and designer Henry Dreyfuss, was introduced in 1953 by the company then known as Minneapolis-Honeywell. The Round became both a sales mainstay and a world-renowned piece of industrial art.

The company eventually known as Honeywell began in 1885 with Albert Butz's invention of the "damper flapper." The flapper opened a damper that allowed outside air to enter a coal-fired home furnace. This increased the oxygen in the furnace and made the fire burn hotter. When the temperature rose to a desired point, the damper closed.

Butz, a Swiss immigrant who had moved to St. Paul in 1881, patented the device. In 1886 he founded the Butz Thermo-Electric Regulator Company in Minneapolis.

Two years later, Butz left the business, but his patents were retained for its use. In 1888 it was renamed the Consolidated Temperature Controlling Company. Andrew Robbins (the namesake of Robbinsdale) became company president in 1889.

William. R. Sweatt, a Minneapolis businessman, joined the company and by 1900, he owned all of it. By then the name had changed again to the Electric Heat Regulator Company.

Sweatt's thermostats were stamped with "Electric Heat Regulator Co" in the form of a semicircle. The first three words formed the arc and the last one appeared within the circle. Underneath the semicircle were the words "Minneapolis, Minn." Because the company often received letters addressed to "The Minneapolis Heat Regulator Company," in 1912 Sweatt renamed the firm yet again.

Between 1888 and 1937, the company evolved. It moved from making one thermostat and one motor to producing more than three thousand control devices and holding a thousand patents. When Sweatt's sons, Harold. W. and Charles. B., turned eighteen, they were named company directors.

Meanwhile, by the 1920s, Mark Honeywell's Wabash, Indiana-based plumbing company was succeeding in the heating-oil business. At the time, oil was replacing coal as the preferred fuel for heating homes.

In 1927 the Minneapolis Heat Regulator Company merged with Honeywell Heating Specialties. The new firm, the Minneapolis-Honeywell Regulator Company, was based in Minneapolis. Harold. W. Sweatt became its president in 1934.

In 1941 engineer Carl Kronmiller and industrial designer Henry Dreyfuss created a round-shaped home thermostat. The project, however, was shelved because of World War II. The Round was introduced to the public in 1953, when Minneapolis-Honeywell was seeking a new product to increase sales.

The T-86 Honeywell Round thermostat—known simply as The Round—was easy to make, easy to use, and easy to identify. Sales to both contractors and homeowners soared.

Minneapolis-Honeywell offered The Round in various shades, to match wall colors. In 1960 a day-night version was introduced. It featured a windup timer for semiautomatic lowering of temperature at night. By 1966, customers could buy a model that controlled both heating and cooling.

According to Jeffrey L. Rodengen's 1995 company history The Legend of Honeywell, about one million units of The Round were sold each year. The Round has also been widely praised as a fine example of modern industrial art. It was featured in a 1997 exhibition of Henry Dreyfuss's work at the Smithsonian Institution's Cooper-Hewitt National Design Museum in New York. It remains part of the Smithsonian's collection.

In 1963 the company's name changed to Honeywell. The group became involved in aerospace, turbochargers, computing, and military weaponry as well as electrical controls. It later shed some of these divisions through new acquisitions and mergers.

In 1999 Honeywell merged with AlliedSignal. Its headquarters moved from Minneapolis to Morristown, New Jersey. The new company kept the name Honeywell because of its strong brand recognition—due in no small part to the enduring popularity of The Round.

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  • Related Resources

Åström, Karl, and Richard M. Murray. "Introduction: Feedback Examples." In Feedback Systems: An Introduction for Scientists and Engineers, 6. Princeton, N.J.: Princeton University Press, 2008. http://www.cds.caltech.edu/~murray/courses/cds101/fa04/caltech/am04_ch1-26sep04.pdf

Honeywell. Honeywell History.
http://honeywell.com/About/Pages/our-history.aspx

Roberts, Kate. "The Honeywell Round Thermostat." In Minnesota 150: The People, Places, and Things that Shape Our State, 77. St. Paul: Minnesota Historical Society, 2007.

Rodengen, Jeffrey L. The Legend of Honeywell. Fort Lauderdale, FL: Write Stuff Syndicate, 1995.

Yarroll, Marie (Manager, Communications and Social Media, Honeywell Automation and Control Solutions), interview with the author, November 30, 2012.

Related Audio

MN90: Honeywell's Hot Little Thermostat | Details

Related Images

Black and white photograph of Honeywell Round thermostats ready for final checkout and packaging at a factory in Golden Valley, c.1955.
Black and white photograph of Honeywell Round thermostats ready for final checkout and packaging at a factory in Golden Valley, c.1955.
Color image of Honeywell Chronotherm counter sign.
Color image of Honeywell Chronotherm counter sign.
Black and white image of Honeywell Round thermostat.
Black and white image of Honeywell Round thermostat.

Turning Point

In 1941, Minneapolis-Honeywell combines engineer Carl Kronmiller's control mechanism with industrial designer Henry Dreyfuss's simple shape to create The Round.

Chronology

1886

Albert Butz founds the Butz Thermo-Electric Regulator Company in Minneapolis.

1900

William R. Sweatt becomes the owner of what is now the Electric Heat Regulator Company.

1927

Now called the Minneapolis Heat Regulator Company, the firm merges with Honeywell Heating Specialties of Wabash, Indiana. The new firm, the Minneapolis-Honeywell Regulator Company, is based in Minneapolis.

1941

Engineer Carl Kronmiller and industrial designer Henry Dreyfuss develop the T-86 Honeywell Round thermostat—commonly called The Round—for Minneapolis-Honeywell. World War II delays the product's release.

1953

Honeywell introduces The Round. It becomes a sales mainstay and a renowned example of industrial art.

1987

A trademark is granted to Honeywell for the word "Round."

1990

Honeywell trademarks The Round's shape.

1997

The Round is included in a retrospective exhibition of Henry Dreyfuss's work at the Cooper Hewitt National Design Museum, New York.