[GWN7]

Air conditioning has been around since 1881. President James A. Garfield was shot and it was a very hot summer in Washington. "In an effort to relieve the sick man from the heat of a Washington summer, Navy engineers rigged up an early version of the modern air conditioner. Fans blew air over a large box of ice and into the President's sickroom; the device worked well enough to lower the temperature twenty degrees"

I'm going with personal computer.