Here in Southern California we're having a major heatwave, and one of my air-conditioners stopped working today. The condenser hums and buzzes, but the fan won't spin, and the air coming out of my upstairs vents is not cool. I tried pushing the fan blades forward with a stick, hoping the capacitor was just bad and once the blades were spinning the unit would work, but nothing happened. The unit is really old, and a bunch of it looks like it was literally chewed away by an animal, probably the big dog the previous owners had.

My guess is that it's not just a bad fan motor or capacitor and that we are going to need a new AC unit. I've never bought one, and would appreciate any advice on what to look for in a new unit, if there are any bells and whistles that are either worth it or not worth it, and any tips for getting comparable bids from companies.