Company Histories in Water Heating
Introduction
Individual inventors created the foundational designs, but manufacturing companies turned those designs into widely available products and continuously refined them. This page profiles the firms that shaped the water heater industry in North America and beyond.
Each entry summarizes founding, key innovations, and lasting influence. Full-length company histories with deeper archival detail will be linked here as they are completed.
Ruud Manufacturing
Founded by Edwin Ruud in 1897 after he left the Fuel Gas and Manufacturing Company.
Ruud had already patented the first automatic storage-tank gas water heater (1890) and followed it with an improved automatic instantaneous design (1898). The company manufactured both storage and instantaneous heaters and became one of the earliest large-scale producers of automatic water heaters in the United States.
The Ruud brand continued after the company’s acquisition by Rheem (around 1959–1960) and remains active today as a Rheem brand, particularly in commercial and residential water heating.
Significance: Direct commercial extension of the most important early automatic designs.
→ Full company history (coming soon)
A.O. Smith
Rooted in a 19th-century metalworking company, A.O. Smith entered water heating through materials science.
In 1936, the company patented a process for glass-lining steel tanks (developed from its work on glass-lined brewery tanks). Residential glass-lined water heater production began in 1939. After a wartime interruption, A.O. Smith scaled mass production in the postwar period and became a dominant manufacturer.
Key later steps included the 1948 acquisition of Burkay (commercial coil and instantaneous heaters) and the introduction of the first glass-lined commercial water heater in the early 1950s. In 2001 A.O. Smith acquired State Water Heaters, significantly expanding its market position.
Glass lining remains the standard corrosion-protection method for most residential storage tanks.
Significance: Made durable, affordable storage water heaters practical for the mass market.
→ Full company history (coming soon)
Rheem
Founded in 1925 by brothers Richard and Donald Rheem (initially focused on steel containers and galvanizing). The company entered automatic gas storage water heaters around 1930–1931 and by 1941 had become the largest U.S. manufacturer of automatic water heaters.
Rheem developed its own glass-lining processes (Rheemglas) in the 1950s and later acquired the Ruud water heater business, preserving the Ruud brand. The company expanded into HVAC and continues as a major producer of storage, tankless, and hybrid water heaters.
Significance: Scaled production dramatically in the pre- and post-war periods and maintained multiple major brands.
→ Full company history (coming soon)
State Water Heaters
Founded in 1946 by Herbert Lindahl Sr. in Nashville. The company began with electric water heaters (1948), added gas models, and adopted glass lining in the 1950s.
State is particularly noted for pioneering polyurethane foam insulation between the tank and outer jacket in the late 1970s — a major advance in reducing standby heat loss. It also developed commercial designs to reduce sediment buildup.
By the 1990s State had become one of the world’s largest water heater manufacturers. It was acquired by A.O. Smith in 2001; the State brand continues.
Significance: Important postwar independent manufacturer and insulation innovator.
→ Full company history (coming soon)
Stiebel Eltron
Founded in Berlin in 1924 by Dr. Theodor Stiebel around his improved coil immersion heater. In 1927, the company introduced early commercial electric instantaneous (tankless) water heaters.
Stiebel Eltron grew into one of the leading global manufacturers of electric water heaters, tankless systems, heat-pump water heaters, and related products. It has maintained a strong focus on electric and energy-efficient technologies.
Significance: Pioneer of practical electric instantaneous water heating and a long-term leader in electric technologies.
→ Full company history (coming soon)
Other Notable Companies
Bradford White — Long-established American manufacturer of residential and commercial water heaters, known for its focus on the professional trade channel.
Rinnai — Japanese company that refined and scaled modern gas tankless technology; major force in the late-20th and 21st-century expansion of tankless systems in North America and elsewhere.
Navien — Significant modern manufacturer of high-efficiency condensing tankless and related systems.
Additional manufacturers and regional firms will be added as research warrants.
Acquisition and Brand Consolidation
Introduction
The water heater industry in North America has been shaped as much by corporate acquisitions and brand consolidation as by technical invention. What began as a field of independent inventors and regional manufacturers gradually concentrated into a smaller number of large firms that control multiple historic brands.
This page examines the major acquisitions and the pattern of brand consolidation that defines the modern industry structure.
Early Independence and the First Major Moves
In the late 19th and early 20th centuries, water heater manufacturing was relatively fragmented. Edwin Ruud’s company, founded in 1897, operated as an independent manufacturer of both storage and instantaneous heaters for decades. Other firms, including early entrants into electric and solar heating, remained separate.
The first significant consolidations appeared in the mid-20th century as production scaled with the postwar housing boom and as materials innovations (especially glass lining) raised the capital requirements for competitive manufacturing.
Rheem and the Acquisition of Ruud
One of the most historically important consolidations occurred when Rheem acquired the water heater business of Ruud Manufacturing (approximately 1959–1960).
Rheem had already grown into the largest U.S. manufacturer of automatic water heaters by the early 1940s. By purchasing Ruud, Rheem obtained both additional manufacturing capacity and a second major brand with deep historical roots in the automatic water heater’s invention.
The Ruud brand was retained and continues to be marketed alongside Rheem products. This acquisition is a classic example of a larger firm absorbing a pioneering company while preserving the historic brand name for market differentiation.
A.O. Smith and the Acquisition of State Water Heaters
A second major consolidation took place in 2001 when A.O. Smith acquired State Water Heaters.
State had been founded in 1946 and had grown into one of the largest independent manufacturers, noted especially for its early adoption of foam insulation and for strong commercial product lines. The acquisition nearly doubled A.O. Smith’s size in the water heater sector at the time and brought the State brand under the A.O. Smith corporate umbrella.
As with Ruud under Rheem, the State brand name was retained and continues in the market. A.O. Smith thereby controlled two of the most significant historic American water heater brands while expanding its overall production and distribution strength.