Nick Baker of Baker Air Conditioning came by today to overhaul the system in 202. He is on our list of preferred providers. He noted that the unit was very dirty inside, likely from infrequent changes of the filter. He even replaced the plywood under the unit that had rotted from the moisture from the unit. From what I saw they did a great job and the new owners should have some cold air this weekend.
I asked him what he was getting now for a total change out. He said he charges $3,400 for a 16 SEER, 3 ton,  Lennox system with a 10 year warranty. From other quotes I've heard this year, that sounds like a pretty decent price.
I did check with another owner about their July bill and she said they also were in the $170 range and rented their 3 bedroom condo pretty fully. They also use Infinite Energy as I do. Owners who experienced much higher bills in July either have a poor electrical contract or a low performing AC system since that's where most of our summer energy is consumed. Besides the evaporating coils being clogged from dust and dirt, the other culprit is often the condenser coils. The environment here erodes the heat dissipating fins in just a few years. They can be treated when new for $500 and is well worth it, but who wants to do preventative work on a new system? Shouldn't they just build them better for this environment?