He was here today and took down a couple of pages of notes, plus notes that I had prepared for him about our specific preferences - things like cold nights/warm mornnigs (I was told that heat pumps don't like being set back that far and get expensive you do that unless you use a special programmable thermostat), humidity, top-notch filtration, what rooms we don't use often and which ones we us frequently, what walls might be affected by potential future renovations, etc. I had professional floorplan diagrams (courtesy of previous owner) but even still he verified the size of all the rooms,measured ceiling height and window sizes, asked about isulation, inspected all closets and places where ducts might run, inspectd the partial basement & crawl space, figured out which direction the house faced, noted the location, height and even type of trees nearby the house, bunch of other stuff. He said he'll probably want to come out one more time before he has a final set of options for us to consider. This guy was recommended by the two main HVAC instructors at the community college where I work as "the only person in this county I ever recommend" because they's both been screwed by recommending others to coworkers and friends who didn't work out, but this guy has done top quality work every time. He does the work himself (with a crew), and doesn't just do the load calculations and design then turn it over to an underling. I talked to five different coworkers (out of a list of around 15) who had used him for significant work and they all highly recommended him. He said he was going to try and work out several options but since my attic is mostly finished space and one of the things he learned is how little many of the 2nd & 3rd floor rooms are used, he's probably going to recommend a regular ducted heat pump system for the first floor and ductless mini-split systems for the 2nd & 3rd floors. Comments and suggestions are still appreciated, since I've only had the one meeting with him so far! Thanks for all your sugggestions - it made me realize even more questions I need to ask.

Yes Natural Gas Furnace for Heating along with the AC condenser. I have read up a lot on zoning, it seems to me like there are not a lot of installers in the industry that really know how to set them up properly. There also is a lot of negative information on zoning as it relates to the troubles a by-pass can cause to your systems efficiency. That is why I was leaning towards the two unit system, however need to figure out the proper size for each level. I know the best thing to run is a Manual J on the place however as a starting point what is the general rule based on square footage in determining the tonnage and BTU for a heating and cooling system? That along with how does the rising of hot air and the dropping of cool air determine the size you would go with? Any help would be appreciated.

Assuming that Manual J is correct (and based on your complaint) you need more cooling. Going the route of new central zoned unit, duct work changes etc. is the expensive fix especially with a relatively new unit already in place. By just buying a mini split heat pump and minor duct modifications you should be able to isolate the bonus room with the mini split and let the air that was going to that room be redistributed to the other rooms. Bonus room is 216 s.f. Not knowing the number of windows or orientation of the bonus room among other things makes it harder to recommend mini split size but as mini splits can "throttle down" the compressor and air flow it's less of a problem if you over sized the unit...I live in Columbia, SC so I'm familiar with the climate. I have a 15,000 btu (1.25 tons) mini split heat pump in my 400 s.f. glassed in sun porch (east orientation so the heating load isn't as much) which does a nice job handling heating and cooling. Even with a south/west orientation I'd think that 21,000 btu might be more than you need for your bonus room.

On Saturday morning I decided to use the same HVAC owner Installer who sold me the American Standard unit in Jan.2000.This man has been my only ac person for over 20 years.I knew him when he was a one man company in the 90's. The lady who does the quote pricing was not there , but he said they would be at my home early Monday morning. I had a written quote for $4997.00 from their service rep. This owner said not to worry the final cost could go up a few hundred dollars. They would remove the old duct work first ,then pick out the most efficient system . The unit was a 3.5 ton - 14.25 seer mid gold series American Standard unit. They would complete the installation by Monday evening. My wife who is in her early 60's started cleaning out the entire attic throwing away many toys for future grand children and moving many heavy items. It was very very hot in the attic. I worked on the attic ladder replacing and tightening loose bolts. We were really exhausted. On Monday morning we were up at 5:00:am and I moved both cars out of the garage to a friendly neighbor's driveway. I even paid him to keep my one classic car in his garage. My wife went to work and I waited and waited ,but no a/c men came.They couldn't even give us a simple phone call. Than around 11:00:am they call and ask me to drive over to their small building. The final price had gone up to $8,300 and if I agree to this , they may be able to start late Monday evening.