The main thing to keep an eye out for here is the rated capacity of the window AC unit (in British Thermal Units, square meters/feet). In this case [Lou] used a pretty beefy $600, 24,000 BTU ...

You can pay for a quieter unit, but this 8,000-BTU air conditioner is the best in its class. Efficient and "quietish," it emits a pleasant low hum, directs air well, and cools up to 340 square feet.