In the middle of a summer heat wave, it's great to have air conditioning. Before Willis Carrier invented his method of cooling indoor air, it was a challenge to stay comfortable in hot weather. A nice, cold drink was helpful, and some homes were designed to make the most of a light breeze, such as the traditional shotgun style homes. Even a nice, big tree for shade was great, but the promise of a temperature controlled home was still very appealing.
In 1902, Carrier's first air conditioner was built to cool a printing plant and remove some of the humidity created by the printing process. After taking out a patent for his design in 1906, Carrier started selling his air conditioning units for commercial applications. And in 1928, he released the Weathermaker, his first home air conditioner [source: Time].
Now that we've got our homes cool, let's get our food hot with the microwave.