About Us


In 1950s Oklahoma City, just as air conditioning was being introduced to the commercial marketplace, IEC was beginning to build its reputation as a reliable, high-performing manufacturer of HVAC fan coil products.

At that time, we were International Manufacturing Company, and were known for offering a wide selection of basic ceiling and floor model fan coil units. Our notable projects included the famed Desert Inn Hotel in Las Vegas, an integral part of the city’s explosive hotel and casino development during the 1950s, and the Drake Hotel in Chicago.
Then in 1961, International Manufacturing was purchased by Mr. Jack Golsen and renamed International Air Conditioning. Under Mr. Golsen, the company aggressively expanded its fan coil product line, to pursue the goal of becoming a full service fan coil equipment provider to the commercial building industry. New product additions included Apartment Series units, Vertical Series sloped top units, Hi-Performance and Belt Drive units. The company’s popular Modular Hi-Rise unit, a standard in many hi-rise structures around the world today, was introduced in 1969.

During the 1960’s, International Air Conditioning established itself as an industry leader by offering customized products or “specials”, a practice that directed the company into the leadership position it maintains today.

During the 1970’s, the company continued to improve on product applications and perfected an in-house turnkey approach with increased emphasis on specials and design/build projects. In 1974, International Air Conditioning was renamed International Environmental Corporation, a move that better reflected the company’s commitment to total air comfort conditioning. Rapid growth at the time warranted a move to the current location of 5000 W I-40 in Oklahoma City.

Throughout the 1980’s and 1990’s, IEC solidified its position as the fan coil industry leader. IEC experienced tremendous growth in highly recognized projects from hotels, office towers and hi-rise condominiums, to schools, universities and medical facilities around the globe.

Today, President Dennis Kloster continues to build on the company’s established leadership position by further enhancing product and application processes and applying cutting-edge technologies to all phases of project development. IEC is continually developing new products for application throughout the worldwide HVAC industry and its markets.