The history of heating in the 1940s might be divided into two parts.

The innovations of the decades before ground to a halt for the most part during the first half of the decade because of World War II. But the balance of the 1940s saw massive production increases brought on by a booming housing market and the increased use of the automobile.

Air conditioning in both of those sectors was yet to come. It was just catching on in public buildings. But with much of the population still in the northern climes, home and auto heating were necessities decades before air conditioning became a “have to have.”

D.W. Norris of Lennox summed it all up in one statement, issued in 1943 to his employees:

“Regardless of Hitler, old furnaces wear out and must be replaced. People are enjoying the highest buying power in all history, and there is little they can buy with their surplus money except replacements of worn-out heating units. A government survey shows nearly three million families plan to buy or build new homes after the war, and millions more are thinking about it.

“Young man, when you get back from this war, go into the furnace business.”

D.W. Norris was ready to go. “Give us the go sign and we can be ready before the steel can get to us from the steel mill,” he said.

But there was still a war on.


Because of World War II, industry manufacturers converted their factories to fill government contracts for war-related materials.

Trane came up with heaters for food dehydration processes, which were important in shipping and preserving foods used by troops. There was also the task of converting building heating technology for use on transport ships.

Lennox got involved in doing a lot of framework for hangars, planes, and ships. Portable furnaces were shipped to army camps. Ever optimistic, D.W. Norris rationalized, “We’re learning new production techniques which are going to be applicable to the furnace business.”

For York, a wartime focus was on heated high-altitude flight suits for pilots. This was one reason that York built a stratospheric test chamber — the Strato-Chamber — to simulate conditions encountered by pilots at altitudes between 35,000 and 40,000 ft. After a cooling period to simulate high-altitude temperatures, “the climb chamber is isolated from the cooling circuit and heated up to normal atmospheric conditions by means of electric heaters,” according to the written history of York.

On the automotive side, several types of car heaters were redesigned for use in military vehicles, as well as aircraft and naval vessels.

One general trend during the decade was an evolution of heating systems from steam and hot water to forced-air systems that combined heating and air conditioning, according to David Arnold’s history of air conditioning published in the ASHRAE Journal.

In the early 1940s, Carrier recognized the need for high-velocity air and began work on an “air and water terminal” in which heating and cooling were transported around the building by water, noted Arnold.

Joining the industry in the early days of World War II was A.O. Smith. The company entered the electric motor industry with the purchase of the Sawyer Electric Manufacturing Co., a maker of small-diameter and small integral horsepower electric motors for use in oil wells.

Domestic production did not grind to a complete halt during the war. “If you retailers think women cannot get a Torrid Zone furnace into a basement, forget it,” said D.W. Norris. “They can.”

By 1944, Lennox began a return to the furnace business — albeit with a few complications. “We have a manpower problem,” Norris said. “Materials are scarce. Railroad service is slow. Trucks are not dependable. Our people are working in two and three shifts around the clock to fill government contracts.”

But, he added, “You Lennox dealers are going to get your furnaces.” If those dealers were upset, Norris told them to “take your frustrations out on Hitler.”


The end of the war flooded domestic manufacturing with able-bodied workers. In some respects, this made finding jobs difficult. But companies ready to step up domestic production of durable goods could find the workers they needed and gear up quickly. It was also a time of experimentation, innovation, and expansion.

Lennox’s D.W. Norris had long predicted a boom in the postwar furnace market. “I can see a tremendous furnace business for 10 years after the war,” he said.

There was a pent-up demand for goods, and predictions of a housing boom abounded. The first step was to convert from wartime to domestic production. For example, Lennox’s Lima, OH, plant, which had produced parts for tanks and bombers, became, in 1945, a major supplier of heating grilles and registers.

Trane focused attention after the war on the development of reciprocating compressors. By 1950, it was manufacturing its own line of recips.


The housing boom required a massive commitment by manufacturers to reasonably priced heating systems. One popular technology was radiant heating. Levittown in New York became famous as the first subdivision to erect mass-produced homes and for the first homes in America to use radiant heat. (See related article, page 43).

Another technology to gain people’s interest after World War II dealt with heat pumps. R.U. Berry of General Electric predicted “a greatly expanded interest in heat pumps in the postwar period.” A small item in a 1945 newspaper article on the topic was noted in a written history of the Refrigeration Service Engineers Society (RSES).

The news item was titled “Heat Pump Idea is 93 Years Old.” The text said, “The reversibility of refrigerating systems has been known for 93 years, but applying this principle to home heating systems is only a few years old. It is predicted many homes will be equipped with heat pump systems within a short time after the war.”

Heat pumps weren’t the only technology getting a boost in 1947. On April 29, the Whirl-A-Way Motor Co. of Tipp City, OH, shipped its first 25 electric motors to Sta-Rite Industries of Delavan, WI. (In 1950, A.O. Smith acquired Whirl-A-Way.)

Also in 1947, Bernie and Bob Greenheck founded a company in a small sheet metal shop in Schofield, WI, that would become one of the world’s top manufacturers of movement and control products.

A 1945 Minneapolis, MN Refrigeration Wholesalers dinner meeting. At the front table facing the camera are Mr. and Mrs. Gus A. Larson.


Advertising became increasingly important in the second half of the 1940s. Lennox launched a national co-operative advertising campaign in major newspapers in 1949. Said the company, “Many dealers report they have always had to first sell the prospect on who Lennox is. This co-operative advertising program will go a long way toward helping solve that problem.

York’s campaign was called “Geared to Go.” The focus was on creative specialty selling, which was a change from the company’s previous emphasis on commodity sales.

The 1940s marked the passing of two Lennox legends. Dave Lennox died in 1947 at age 92. Company president D.W. Norris passed away in 1949 at age 73.


The postwar boom extended beyond homes, offices, and stationary structures. The automobile took on a high profile.

During the 1940s, there was an awareness of the benefits of heating and cooling systems employing ventilation. The trend was toward the use of fresh outside air for car heaters. This helped in de-fogging windows and keeping positive auto body pressure in order to avoid the infiltration of cold air.

In an extensive history of auto heating by Mohinder Bhatti published in the August 1999 ASHRAE Journal, the author reported that in 1941, Buick was using an outside air underseat heater as well as an outside air defroster.

By the end of the war, carmakers returned to domestic production with heating systems dating from 1942. Heat pump technology also found its way into automotive design. Bhatti reported on the development of a heat pump system for a two-passenger subcompact coupe, which was the first time the technology was used in a commercially produced car.

In the 1941 model year, automatic temperature controls were introduced to car heating systems. “The control was achieved by means of temperature-sensing elements such as liquid-filled bellows or capillaries that were placed to sense in-car temperature,” wrote Bhatti.

A year later, Ford offered factory-installed fresh air hot water heaters. “They were integrated with the standard ventilation system and included a thermostatic valve.”

There were problems with the technology. “If the control valves were repositioned for less heat, it would completely shut off the water supply to the heater core, causing a cold blow,” said Bhatti. He noted the deficiency was overcome in 1950 with a redesign.


Some of the technologies developed for the war were carried over for domestic use at the war’s end. But for the most part, what had been created in the 30s carried on into the 50s. That’s because existing furnace, boiler and other heating technologies had to quickly get into those houses and buildings that were being rapidly erected in the years following World War II. On top of that, air conditioning was starting to catch on, and that technology required a great deal of research and development, followed by rapid manufacturing.

Sidebar: The Father Of Radiant Heating In America by Dan Holohan

Our fathers returned from the war and moved their young families from New York City to the “country,” where they bought or rented these inexpensive homes and set out to live the American Dream. About 10,000 of these cookie-cutter houses were in Levittown and these were the first radiantly heated homes in America. Thousands more of these little dwellings wound up in Hicksville and Bethpage and radiant kept us cozy while we were growing up.

Irwin (Jal) Jalonack made the decision to use hydronic radiant heating in Levittown in 1946. These were the first mass-produced homes in America. Levittown introduced the American consumer to radiant.

Recently, Mr. Jalonack’s daughter, Carol Blum, wrote to tell me about her father:

“The idea was to build an inexpensive house that could be run economically. Clearly, building on a slab was the way to go. My father felt that forced air was not good. He made the decision to go with oil heat, and then went looking for an oil-fired boiler that was small enough to fit in the kitchen, right next to the other appliances.”

Mr. Jalonack found that little boiler. It was made by York-Shipley and the trade dubbed it the “low-York” because it was just a bit taller than a washing machine. Most of those boilers continue to heat those Levitt homes to this day.

William Levitt followed the methods of Henry Ford when he built his houses. He managed to throw them up at the incredible rate of one every 2 hrs! And since these were America’s first radiantly heated homes, much of the engineering was experimental. A lot of what they did in those days they made up as they went along. Things that we consider to be crucial to radiant design nowadays never made it into those Levitt homes. For instance, they used no insulation whatsoever under the slab or at the edges of the slab.

Levitt also didn’t bother with a vapor barrier beneath the slab because that would have added too much expense. As time went by, and as the copper tubing began to leak, the water soaked into the ground rather than rose up through the floor. As a result, the homeowners didn’t know when a minor leak occurred, and that led to major leaks as time went by. Many of these systems were abandoned after 20 years or so.

Holohan is a writer and longtime contributor to The News’ sister publication, Plumbing & Mechanical. This excerpt is reprinted with his permission from his website,

Publication date: 11/12/2001