Founded in 1921, Johnson Air-Rotation HVAC Systems set the bar by creating a new technology now known in the industry as Air-Rotation. Don’t be fooled by imitators referring to air turnover. Over the decades, Johnson Air-Rotation HVAC Systems have continued to innovate and refine the concept to create the most effective method to heat, cool, filter and/or ventilate large, open buildings. Johnson Air-Rotation HVAC Systems have been proudly manufactured in the USA since our beginning and continue to be to this day. As the ONLY UL® listed Air-Rotation/air turnover system in the industry, we take pride in our custom manufactured product and you will too. Johnson Air-Rotation HVAC Systems is the leading manufacturer of industrial heating and cooling systems and warehouse HVAC.