clockwork you will always get more comfort and control from multiple systems over a single system with zoning controls. however, a zoned system like you have listed is certainly a viable second choice and not overkill. dealer must do his load calcs for equipment and Man D for ductwork sizing/design. Ductwork should be insulated probably R8. I would want metal trunk lines for both supply and return. what did dealer propose? I think your biggest challenge is verifying your dealer's experience/expertise with a sgl system using zoning controls. I recommend going to visit a newly constructed home similar to yours where zoning controls were used and discuss with homeowner. Zoning is not for the inexperienced. how much is this system? IMO Good Luck!

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.

The Utra tech Copeland scroll compressor unloads at 67% capacity. The scroll compressor is 95% efficient on high speed and 94% on low. This is why the scroll at this time is the number 1 compressor for residential application. when it works it works efficiently. However there is other factors for your over all application. coil size of evaporator, fan speed, coil temperature to regulate your TXV metering valve. ect.. Copeland states their 2 speed ultra compressors take 53% more humidity out of the air then their single speed compressors, I will have to find out what this means, is it combined with variable speed or just a constant cfm. Data on the 286B 2 ton 286B with FE4C-3 23,000 btu high 19,400 btu low 3 ton 286B with FE4C-5 36,000 btu high 29,400 btu low 3 ton 286B with FE4C-3 34,600 btu high 28,600 btu low what you want in a two speed system is for your system to run at low speed most of the time. It will take less energy and take out humidity. your 286B is similar to the 226A but with data control so since I'm in Fl and we don't have the 286B yet I will say that it should run around 4.8 to 5.5 amps in low spead around 8.5 to 10.5 amps in high. You want the high speed for the time of day that it is the most hot and days that it is very hot. two speed with variable speed air handlers have change the way we think or I think. And it has nothing to do with what the data specs say or what a computer tells me the thing should be. As we discussed most load calculations unfortunately are used for sales pitching. It's not the exact, it just gives a frame of reference so a professional can make his decision. No two programs will give you the same btu nor will two people give you the same end btu it's just a frame of reference. Data in is data received and we all perceive data differently. I've done loads since they came out on DOS back in 1989. It is only a guide for me not an end all. Let me say, that we can get even more precise, with a home energy audit and HERS rating with a blower door and duct blaster test. We can also grade your insulation, yes it's just not about R-value there is 3 levels of how the insulation was installed. It gets so ridiculous that it has become ridiculous. You may have to look at your home, see how your old system performed. Did it run all the time last summer? We had a hot and rainy summer last season. All these factors I use when I give a bid to a customer. I really focus in on the customer gut feeling too and what temperature is your comfort level. Many Manual J are based on 78F temp in side your home. Well what if you like it at 72F and what if it get's 98F and stays there for 2 weeks? Then this should be changed in the manual J for a proper rating. You know your energy bills, you know that the system before either ran too much or not enough, or it was pretty much out of site out of mind. The good thing is that over sizing is not like it was 10 yrs ago. There is variable speed air handlers and 2 speed compressors that can regulate humidity and your comfort level and this is what we are trying to accomplish, a comfort level in the most efficient way that doesn't cost a million banana's If there is a concern, you may want to look at the FE4C-3. it looses a .5 SEER but has less btu's and it is a slant coil that is much easier to clean. It is very hard for me to give advice since I have not physically looked at your application, but I do know you have a very good contractor that should take care of your needs.

Get more bids. A crane sounds expensive, but in the past a small sign crane rented for $75 per hour in N. Texas. The sign company rented thier cranes all over a 5 state area. A medium sign crane rented for $125. I would imagine today the small would still be less than $200. If the contractor is on the ball, and knows how to do it, the crane should only take about 15 minutes. Put the new unite on the roof, and remove the old unit. I have set a lot of junk on roofs, it aint rocket science. Even if the crane cost $500, your bid is still high enough for me to fly first class and do the job, enjoy the sights for a week eat at the most expensive restraunts and fly home.