Today, Amana® brand heating and air conditioning is part of one of the leading manufacturers of energy efficient residential, commercial and industrial HVAC systems and refrigerants. Gas furnaces use natural gas to heat air as it moves through a series of ducts, which then is sent to your house via grilles and registers. By far the most popular way of heating a home, Amana furnaces are efficient, reliable, and will bring your home warmth in the colder months for many years.