Willis Haviland Carrier is the man to thank on those dog days of summer when the temperature soars and the only thing to look forward to is coming home and turning on your AC.

In 1902, Carrier developed the very first air conditioner unit for the printing company he was working for shortly after he graduated from college. Carrier was inspired to create the air conditioner because of some printing problems his firm, the Buffalo Forge Company, was having. Major fluctuations in heat and humidity began to cause the dimensions of the paper to shift, which, in turn, caused a misalignment of the colored inks. Thanks to Carrier's invention, fluctuations in temperatures were no longer an issue and aligned four-color printing became possible.

Though Carrier is often called the "father" of air conditioning, it was actually a textile engineer named Stuart H. Cramer who coined the term "air conditioning" (Carrier called his unit an "Apparatus for Treating Air"). Cramer developed an air conditioner that added water vapor back into the air in textile plants to help condition yarns.

Carrier developed his unit for a printing plant, but many other industries soon benefited from his air conditioning invention. Tobacco, textiles, pharmaceuticals, food production and many other products all acquired significant improvements in quality. In 1911, Carrier presented his basic Rational Psychometric Formula to the American Society of Mechanical Engineers and this formula still stands today as the fundamental basis for calculations used as standard in the air conditioning industry.

In 1921, Carrier took his invention even further by patenting the "centrifugal chiller." This chiller was the first development in the cooling industry that tackled the issue of how to cool off large spaces.

The J.L. Hudson Department Store in Detroit, Michigan took Carrier's invention one step further in 1924, when their store became the first air conditioned department store in the country. Customers loved the experience of shopping in this cooled off environment, and other retailers followed suit. Soon, movie theaters joined in the mix, and the Rivoli Theater in New York City was one of the first to begin advertising that patrons could enjoy films while sitting in the cool comfort of their air conditioned seats.

Finally, in 1928, Carrier introduced the "Weathermaker," which was the first air conditioner intended for use in private homes.

Though the interest and widespread use of air conditioning slowed a bit during the Great Depression and World War II, consumer interest eventually returned and today millions of people enjoy the cool comfort of air conditioning in their homes, cars, workplaces, and anywhere else they spend time in the heat.