Albert M. Butz developed a thermostatic system in Minneapolis which automatically adjusted room temperatures in residential buildings. The patents were registered in 1885 and the "Butz Thermo-Electric Regulator Company" was established. It was the first company to offer the product for the automatic regulation of internal temperatures in buildings.
In 1888, Butz left Minneapolis, and his patents were held by attorneys in the "Consolidated Temperature Controlling Company". Four years later, the name was changed to the "Electric Thermostat Company", and William R. Sweatt assumed management of the business. Ten years later, he became sole proprietor of the business, operating under the name "Electric Heat Regulator Company".
The company built its first factory in Minneapolis in 1912, and changed its name to the "Minneapolis Heat Regulator Company".
In 1924, Mark C. Honeywell, a pioneer in automation technology, developed clock-controlled thermostats in his company, "Honeywell Heating Specialties Company".
Three years later, Sweatt and Honeywell merged their two companies together under the name of the "Minneapolis-Honeywell Regulator Company." Sales reached $5.25 million in 1928, and $100 million in 1945 and $1 billion in 1967.
Today the company is called "Honeywell International" and based in Morristown, New Jersey. After multiple acquisitions, expansions, reorganizations and mergers, it has a huge range of products and over 116,000 employees and annual sales over $30 billion. (info from Honeywell and Wikipedia)