Willis Carrier invented air conditioning in 1902. Let’s take a look at how it has changed since then.

In 1914, the first residential air conditioning units took up 840 cubic feet of space. Today, standard home HVAC units only occupy about 36 cubic feet.

In 1932, the first room air conditioners cost about $50,000 — $860,000 in today’s dollars. Prices dropped quickly; by 1938, the average cost of a window unit was only $416 — $7,250 in today’s dollars. In 2019, the average window unit cost $200.

In 1939, Packard became the first manufacturer to offer air conditioning in cars. The option cost $274 — about $5,000 today. Now, air conditioning is standard equipment in most new vehicles.

Air conditioning has become much more common through the decades. Before 1940, only about 50% of homes had central air conditioning. These days, about 91% of homes are equipped with central air conditioning.

Today’s central air conditioning systems are much more efficient, using about 30% to 50% less energy to produce the same amount of cooling. In the mid-1970s, the average home used about 40 kilowatt-hours (kWh) a day for cooling. In 2019, that number had dropped to 28 kWh a day.