I live in a 2 story 1800sq.ft. house built in 1987 in Southern California and it's getting pretty hot now and I'm getting tempted by the rebates being offered ($1700.00).
I still have the original HVAC system which seems to be working fine (or the same as it has since I moved in 9 years ago) which is as follows
Lennox Conservator III
Lennox HS18-511-3P (4 ton 3 phase?)
I've had it serviced less than a year ago and am very good with the filters as well. Even my energy bills aren't that much, just under $200/mo for both electrical and gas.
My biggest complaint, which I hear a lot, is how difficult it is to cool rooms upstairs. The only way to get it under 80 is to close all the down stairs vents and set it to about 72 and it still takes 2+ hours and that's in the evening. I've also taken a quick at the ducts which seem fine.
Sounds like if I was to replace it this may be a good time but would it be mostly a waste? I know it won't pay for itself anytime soon but would the newer units make a big difference in comfort especially upstairs without running all day? I also don't want to do a major upgrade price wise just a newer possibly slightly higher level system.