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Air Conditioning History: Margaret Ingels

Air conditioning history is relatively short. It has only existed since the early 20th century, in part due to engineering pioneers who developed temperature control technology. At Douglas Cooling & Heating, we are big fans of air conditioning history, as you can imagine.

Did you know without the contributions of pioneer Margaret Ingels, we wouldn’t have air humidity measurement tools or have come nearly as far in air filtration technology? This Women’s History Month, we celebrate Ingels and her many contributions to air conditioning history.

Early Life and Education

Ingels was born in 1892 in Paris, Kentucky, and had an interest in science from the start. As a young girl, she watched moisture collect on glass and became curious about condensation. This curiosity eventually led to a successful career in air conditioning.

She enrolled at the University of Kentucky with intentions to pursue architecture. Because the school didn’t have such a degree program yet, a dean persuaded her to study mechanical engineering instead. She thrived and served as secretary for several engineering groups before she graduated with honors.

In 1916 she became the first woman to graduate from the school’s College of Mechanical Engineering. She was the first woman at the school to earn an engineering degree and only the second female engineering graduate in the United States.


After college, Ingels worked in the traffic engineering department for the Chicago Telephone Company. She moved to Pittsburgh in 1917 to work for the Carrier Lyle Heating and Ventilation Corporation, where her interest in air conditioning began.

She received the Mechanical Engineering professional degree in 1920. The next year she joined the American Society of Heating and Ventilating Engineers research lab, where she studied air conditioning for six years.

In 1931, she returned to Carrier-Lyle, where she worked until retirement. Ingels helped develop the Anderson-Armspach dust determinator, which became the industry standard for air filtration, and the sling psychrometer, a relative air humidity measurement tool still used today.

Her career also included working in a U.S. Bureau of Mines laboratory to help create air cleanliness standards.

Industry Advocacy

Ingels’s contributions to air conditioning history weren’t limited to her work in laboratories. She also served as an advocate for the profession. From 1932 to 1952, she wrote more than 45 technical papers. She also traveled across the country to deliver more than 200 speeches to more than 12,000 people.

Her most well-known speech, “Petticoats and Slide Rules”, documented “the pioneer American women of the engineering field.” In it, she wrote female engineers had a responsibility to “widen the trails blazed for her — and more. She must build them into great highways for women engineers of the future to travel, free of prejudices and discrimination.”

Awards and Recognition in Air Conditioning History

Her advocacy and professional achievements earned Ingels several accolades throughout her lifetime. Along with 100 other American women, including Eleanor Roosevelt, she was selected to the 1940 Women’s Centennial Congress, which recognized females who had successful careers in fields not open to women a century earlier.

Her alma mater also awarded her an honorary law degree in 1957 and inducted her to the College of Engineering’s Hall of Distinction in 1993.

Improve the Comfort in Your Home with a Call to Douglas Cooling & Heating

Thanks to industry pioneers like Margaret Ingels, air conditioning technology continues to evolve and improve the comfort levels of homes in new and innovative ways today.

If you need help choosing a system for your home, our expert team at Douglas Cooling & Heating in Birmingham knows air conditioning and is happy to help you to find the most efficient and dependable equipment for all your home comfort needs. Contact us today to schedule a service call or consultation.

We serve the Birmingham, Alabama area including Bessemer,  Homewood, Hoover, Calera and Mountain Brook. You’ll also see our trucks in Chelsea, Pelham, Vestavia Hills and Helena. Finally, we’ve recently introduced plumbing services to better serve homeowners. Give us a call with plumbing or HVAC needs!

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