The year was 1919. And in the city of St. Louis, the air pollution was so thick that candles were needed to see during the day. Local evergreen growers even refused to sell trees to city residents. All of this was because of the extensive use of wood- and coal-burning furnaces. Nortek Global HVAC got its start as the International Oil Heating Company, manufacturing environmentally friendlier oil burners for home heating. After success with St. Louis’ pollution problem, the company took its oil burners and coal conversion kits nationwide.