re: Ways to keep house cool while waiting to repair AC situation.

Make sure the HVAC guy is looking for any loose ducts leaking air into the attic. This would both cause you to loose conditioned air and also create a negative pressure inside which would pull outside air in from any possible air leak.

Which brings up another point, if you have a bunch of recessed/can lights they leak like a sieve if not air sealed. Which brings up another point, you mentioned a powered vent, those things are almost always worthless. Not that they don't move air but they cause more problems than solve. #1 is they can create a negative pressure in the attic which causes some conditioned air to be pulled from any of the aforementioned air leaks. (can lights are a big one). This is made worse if you have limited intake/soffit ventilation.

Contrary to intuition, the temp of the attic air isn't as big of deal as you would think. Best money spent is usually on better insulation.


To address your specific question, DON'T get one of those portable "one hose" ACs. I won't go into why those things are such garbage but you can youtube it for a demonstration. If no duct leakage, and sans a bunch of leaky recessed light, a window shaker or 2 hose portable until is your best bet until you can upgrade your system.