The central heat and air in the house I'm renting is unable to keep the house below 80 °F during the hot summer here (100 °F days). We've had 3 HVAC techs out to look at it and they all say there's "nothing wrong with the system" and that it's "sized appropriately." The latest said perhaps it's just a combination of small factors (old house, leaky windows, etc.).
The property owner is going to provide me with two window units to use - one in the bedroom and one in the living room. Would it be more efficient (in electricity cost) to turn off the central AC entirely and rely on the window units, or better to run all three systems?