Thanks tigerdunes. From reading many of your responses to other threads, I was ready to hear you ask if other brands were available. Our builder is a custom home builder but I know he has a pricing agreement with the contractor for all of his homes. I will inquire about the possibility of a different contractor regardless.

Elite series on all components - condensers and furnaces? I admit I like the idea of getting to the better components in the Elite level but the upgrade costs seem excessive to get there. In previous threads, I have found recommendations against spending $1k to upgrade from the ACX series to the XC series due to the prohibitive pricing.

The structure will be a 1 1/2 story with a basement. Both furnaces will be in the basement. Main floor unit will have all ductwork in the basement feeding up to main level. Second floor unit will have ductwork running up to attic above second floor living area with ductwork running in unconditioned space.

An additional question - what about the possibility of consolidating to a single system using zoning vs two systems? I imagine this would allow you to have a very nice staged system inside and out for the same pricing. Since this is a new build, we could do whatever it required for ducting from the get go.

the ACX condensers are Mexican POJ. I would not have them. Yep, the upgrade pricing is absurd but typical on new home construction/GCs. If sticking with Lennox, I would go with Elite series both furnace and AC condenser. Discuss upgrade pricing with your GC. Tell him how disappointed you are. I am not against zoning. The downside from two dedicated systems are some redundancy loss and comfort. You probably will save some money. You would want to qualify your dealers/installer's experience in this area both equipment and ductwork design. It would allow you to upgrade to top of line modulating furnace and var speed AC condenser which you would want since your zones are different sizes.

IMO

If I was to get my pick of manufacturers to pursue, who would you recommend?

My picks are Carrier/Bryant and Trane/AmStd. Of course Lennox is considered one of the big 3 but I think there is a wide separation between them and those that I mentioned. But I am really disappointed with Carrier and how they treated their employees when they announced several mths ago they are moving their manufacturing operations to South of the Border. With their pricing Lennox thinks a lot more of their products than I do. I do not like their evap coils. And as far as one brand and zoning, Carrier/Bryant offer the best integrated residential zoning systems on the market.

IMO

Both furnaces will be in the basement. Second floor unit will have ductwork running up to attic above second floor living area with ductwork running in unconditioned space.

This is a bad way of running the duct work. Why can't the duct work for the second story run in the floor and use floor vents? This will keep the duct work in conditioned space and also provide shorter runs.

Mike is correct but ductwork installer has to get design/size right because there is no going back...

IMO

I don't know if there is much we can do about the upper level ductwork. I'm guessing something like that would require soffits to be run below the upper level and given the open ceiling floor plan beneath the upper level, that might be a tough suggestion to make.

Mike - do you have any comments on the grade of components recommended? I realize this is a tough ask - not sure anyone would argue that the Elite series Lennox units are better than the Merit units. It's more of a consideration given the upgrade expenses.

Questions opened up to the builder on possibly another choice on HVAC sub. We'll see how that goes.

Can anyone comment on the relative use each of these systems would see? Is the main level unit going to do 80% of the work while the upper level unit will only see limited use? Would that figure into the weight given to upgrading each system?

Just to say it, I'm somewhat leaning toward upgrading the main level unit to the var spd EL296 to get the comfort benefit of the variable speed. Is there any advantage to upgrading the AC unit for that system to the Elite series beyond sound level and component quality? IE - are there any system benefits of the EL296 that would be left underutilized if paired with the 14ACX vs an XC16?

The floor joists are most likely 2X10 lumber. The builder should be able to run the duct work parallel to the joists. This is how it was done in my house. If this is a custom home builder then I would think he could modify his plan.

I am not that familiar with Lennox, but in any brand I would stay away from the builder grade level. I personally think investing in variable speed furnaces and 2-stage AC makes sense. Unfortunately builders like to make big profits on upgrades.

The nice thing about two independent systems is that you can set back the temperature on each floor when not in use. The upstairs AC will potentially run more in the summer because heat rises and it sits under a hot attic. In the winter some of the heat of the first floor will rise to the second floor, but the second floor has a bigger heat loss because of the attic. The two may balance out each other.

Good comment on the execution of subfloor ducting. At this point, the home design is complete, engineering plans approved and we're ready to begin foundation excavation. Guessing we're too late to change the game plan for the ducting. As it is, we have a chase planned near the middle of the floor plan to get the ducting up to the attic.

Also like the comment about setting the different living levels at different setback times. Hadn't thought about that.