In 1908, G.B. Wilson authored a book titled “Air Conditioning, Being a short treatise on the Humidification, Ventilation, Cooling, and the hygiene of Textile Factories – especially with relation to those in the U.S.A.”. Wilson created what is thought to be the first functional definition of air conditioning. This same definition is what Willis Carrier, the “father of air conditioning” adhered to in his manufacturing of air conditioners.

• Maintain suitable humidity in all parts of a building.
• Free the air from excessive humidity during certain seasons.
• Supply a constant and adequate supply of ventilation.
• Efficiently remove from the air micro-organisms, dust, soot, and other foreign bodies.
• Efficiently cool room air during certain seasons.
• Heat or help heat the rooms in winter.
• An apparatus that is not cost-prohibitive in purchase or maintenance.

For the most part, these statements still accurately define what modern air conditioning systems accomplish today, more than 100 years later.