In the midst of the current nationwide heat wave, take a moment out of your day to say thanks to Willis Haviland Carrier. Who's that? His last name—Carrier—should provide a clue.

Carrier is credited with inventing air-conditioning—he received a patent for a system to control heat and humidity way back in 1906.

Consumer Reports didn't start testing air conditioners as long ago as that, but we have been at it for many  years. In the 1957 photo shown here, a technician mounts an air conditioner inside a special chamber as part of a room-air-conditioner test. The strands running about are thermocouple wiring used to determine the uniformity of air temperature in the room.—Steven H. Saltzman

Essential information: Read this recent blog entry to learn which air conditioner to buy for your home.