Since ancient times, people have sought ways to make the buildings in which they live, work, and play more comfortable.  Today, the Heating, Ventilation, and Air Conditioning (HVAC) industry provides the means to control the temperature, humidity, and even the cleanliness of the air in our homes, schools, offices and factories.  The men and women of the HVAC trades are highly skilled workers who install, maintain, and repair the equipment that keeps people comfortable and business and industry running.  The US Department of Labor and other similar organizations continue to rate the HVAC field(s) as one the best returns on educational investment to wages one may earn.