I am faced with a similar conundrum. I NEED to replace both HVAC systems in my home -the upstairs unit quit three years ago and the downstairs unit is hanging by a thread.
$17,000 for a pair of lower end systems. Double that at a minimum for the highest efficiency systems.
I have installed window units in the meantime and I need one more window unit to completely negate the NEED for central air conditioning. (It is Hot as Hades here in the summer, BTW).
$17,000 to save $100-$150 per month is a hard pill to swallow now, but I will have to replace it all before I sell the home, whenever that may be, and if I wait until I sell I will have received zero benefit from the purchase.
Solar panels are BS in my opinion, for now. The GREEN cost to manufacture in terms of GREEN energy far outweigh their benefit to mother earth, not to mention the economic comparison to my situation above.