I know a little about HVAC.
Here's what I would do (and have done in your situation)-
Install a single, "mini-split" multi-port heat pump condensing unit and two indoor ducted, multi-position air handling units inside. One for downstairs, one for upstairs. The most idiotic thing to come about in the last 25 years is the use of zone damper systems in residential construction where a single system serves multiple floors. They simply do not work. To equate that to your line of work, Mr. Critic - that is the same as putting 4 different wheels and tires on a single vehicle because the owner wants to drive over turf/pasture (wide turf tractor wheel/tire), go rock crawling (18" x 12" wide wheel with a 35" x 12.50 x 18 Patagonia tire; run highway speeds daily (20" x 9" wheel with Michelin LTX M/S tire) and an 18" steelie with a snow tire because the owner goes to the mountains on the weekends in January/February.
What kind of sense does that make? About the same as a single unit serving two-three floors.....
My suggestion - sounds like you need a 4-ton multi-port condensing unit and two indoor units, probably a 3 and a 2-ton. Brand? Daikin.
Your climate will support a heat pump very well. I suspect your power bill will reduce enough to pay the PREMIUM this system will cost over the same old chit that the contractors are suggesting to replace the existing.
Feel free to PM me if needed.
Edited.....
HOLY CRAP at those electric rates..... BTW, you won't need gas with my suggestion...
Also, I wrote a song about all this-
I generally stay out of the home HVAC threads because, well, most people want to know what the cheapest solution is. I saw in the latest thread someone asking about mini-splits. There's several versions/product lines of "mini-splits". First off, I have been a fan of the newer technology of...
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