HVAC History: The History of Stewart-Warner Furnaces

When most people hear “Stewart-Warner,” they think of classic cars and dashboard gauges, but the company also had a surprising role in heating American homes. Starting in the 1920s and ’30s, Stewart-Warner expanded into HVAC, producing oil and gas furnaces under names like “Heatmaster.” These units were modern for their time: compact, automatic, and built with the same engineering precision that made their instruments famous. With post-WWII housing on the rise, their heating products found a place in thousands of basements, offering a reliable and stylish alternative to bulky coal systems.

A major turning point came when Stewart-Warner acquired Winkler Furnace, a respected name in oil burner technology. Winkler had already pioneered efficient oil-fired heating in the early 20th century, and under Stewart-Warner’s ownership, their units became even more widespread. Branded as “Winkler by Stewart-Warner,” these furnaces were known for their dependable burners, solid construction, and distinctive industrial look, often with bold logos and brushed-metal control panels. They became a go-to choice for homeowners and technicians alike during the 1940s through the ’60s.

Showcasing many of their innovations they employed creative logos to keep up the appeal of the decade. Showcasing their distinct style, laid out some of their designs that you’d have found on their furnaces and boilers. (Fig. A) shows a dataplate, (Fig. B) shows a typical style found on their higher end models. (Fig. C) shows a small plate that would have been found as an additional emblem on top of the existing one on all models. and (Fig. D) showed their mid range furnaces/boilers and for the economy was on (Fig. E)

Fig. A

Fig. B

Fig. C

Fig. D

Fig. E

By the 1970s, Stewart-Warner began stepping away from the HVAC business as competition from major players like Carrier and Lennox ramped up. Though the Winkler name faded, many of their furnaces continued to quietly operate for decades. Today, they’re remembered not just as heating units, but as symbols of an era when American companies took pride in designing machines that lasted. Stewart-Warner and Winkler may not be household names in HVAC anymore, but their legacy still lingers in the warmth of mid-century homes across the country.