Indoor cooling and heating is by no means a new idea. While we often look back on history and think “how did they ever live with no air conditioning unit?” people have been coming up with ways to manipulate air indoors since ancient times!
In ancient China, during the Han Dynasty, the first mechanical rotary fan was invented. A single person could turn a wheel and cool an entire room with a system of interconnected fans. This invention underwent many changes throughout history until electricity rose to prominence and rendered them obsolete.
When did the age of modern HVAC systems begin, you may wonder. Let’s take a more in-depth look at how your cooling and heating unit came to be!
Invention

Willis Carrier drew up the first design for our modern HVAC systems back in 1902. He applied for a patent for it two years later and called it Apparatus for Treating Air.
Carrier was the first man to come up with a way to successfully control indoor humidity and discussed it in his essay Rational Psychrometric Formulae. Today, the document is known as the most important document ever written about psychrometric formulae.
HVAC System

- Thermostat– Regulates temperature by communicating with the furnace to tell it when to turn on and off.
- Furnace– Houses almost all of the other major components to your HVAC unit.
- Heat exchanger/ evaporator coil– Warms/ cools the air that comes into the furnace to keep your home at the desired temperature.
- Condenser– Condenses refrigerant gas into liquid form to be carried by refrigerant lines to the evaporator coil, which uses it to cool your home.
- Air ducts and vents– Direct air from the furnace to different areas of the house and back again. Vents are often located in the ceilings or floors of each room.
Old Air Conditioner

The date of manufacture can usually be found somewhere on the unit itself, either on the manufacturer nameplate tag, or hidden in the serial number.
Knowing the age of your unit is essential because it can save you from paying for unnecessary, costly repairs on a unit that is better off being replaced. Call Cardinal Heating today with any questions you may have about replacing your old HVAC system! Speak with a qualified HVAC Professional in Sun Prairie today when you call 608-470-3876 .