for Pickens I suspect that for over 99.9% of homeowners, two stg condensers whether AC or HP are overkill and unnecessary. The exceptions are usually for improved dehumidification, oversizing on HPs to get the extra BTUs on the heating size, and of course the main reason would be for zoning. And if I was going to buy a two stg condenser, I want one that has good dehumidification properties with a 50/100 output split. I would not have the older mdl XL16i which has questionable dehumidification properties, a 70/100 output split. The new improved model is better but I still prefer the XL15i. wish I did live in Clemson but am relatively close in the upstate area. for e171fish I want to see the load calcs in writing with the printout from the software that produced the numbers. I would not use one system for the main floor and basement without the zoning controls and Carrier offers perhaps the best residential integrated system as any major brand. you do want to qualify the dealer's credentials/experience in this area. The FE5ANB004+UI has slightly better numbers than the FE4ANF005. for the second floor, you could drop the two stg for the sgl stg Performance 15 HP which is one of the best on the market and has better performance/eff numbers. I can't comment on the geothermal other than to say if you have the land, the money, and plan to live in the home many years, then geo is the way to go if operating costs are important to you. If I understand correctly, the Trane quote is less expensive and includes three systems, one for each floor. I really like that idea better. You do want to use the HW VP IAQ stat for each system. IMO

"I appreciate any advice you can give. I know that this isn't the ideal approach to selecting a new system, but I'm very happy with my GC overall and am looking for the "best compromise" rather than a big fight." zyll I have to admit I don't like the above statement that I see frequently from other posts/HVAC forums. Why? You are the customer and it is your home that you will be living in. You are making the purchase and should get what you want, not what the GC wants you to have. Here are my ideas on new HVAC whether for new construction or replacement. 1.What is the builder budget/allowance? 2.What comfort level are you looking for? 3.Upfront cost not necessarily same as item #1 if you elect to upgrade 4.operational cost and efficiency of new HVAC 5.correct sizing of both new HVAC and ductwork (has GC or HVAC sub made his calculations and reviewed them with you?) 6.good quality equipment 7.good install from a dealer who has excellent qualifications. The more the homeowner knows, the better chance for an informed decision that will lead to a successful install and a satisfied customer. Now, everyone knows fuel rates are on the rise, especially fossil fuels like nat gas,propane, and oil. After looking at your fuel costs, you obviously would be candidate for a geothermal system. As a rule of thumb, they are usually two to two and half times the cost of a conventional system. But for the moment, I will assume you want a conventional system and will live in this home for the forseeable future. I have used your rates and for efficiency used a COP of 2.75(HP) and an AFUE of 93%(furnace)-tried to be conservative. Numbers were plugged into fuel comparison calculator. Cost per 100,000 btu of useable heat Electric baseboard: $1.89 Heat pump: $0.76 Natural gas: $1.34 You are a great candidate for dual fuel-a heat pump with nat gas backup furnace. Now to your question about Trane and for disclosure I have a 3 yr old Trane dual fuel system myself. First off, throw overboard the XB equipment, both furnace and AC. Low end. I would not have it. for dual fuel My budget choice would XT90 or XR90 furnace with XR14 heat pump My premium choice would be XV95 or XV90(if available) with XL15i heat pump without dual fuel-furnace with straight AC budget choice XT90 or XR90 with XR14 AC premium choice XV95 with XL15i or XR14 AC My personal choice is XV95 or XV90(if available) with XL15i heat pump Of course you will need a stat,matching evap coil for either AC/HP condenser, and some type of air cleaner cabinet. I have to admit that Carrier Infinity and Bryant Evolution dual fuel systems with their sophisticated controllers are the best in the marketplace. IMO www.trane.com www.carrier.com Here is a link that might be useful: Fuel Comparison Calculator

I take an entirely different tack. First off, I will not disagree about whole house humidifier for comfort. But even more important because of new construction and I will assume is top of line building and insulation qualities(it should be!) is a fresh air exchanger. Yes, houses built today can be too tight. Next, why take a premium home and not include a premium HVAC system? Dumb idea. While you didn't specify, I will assume nat gas service availability. I would want high eff modulating furnace. Brands would be Carrier/Bryant and Trane/AmStd. If you want to drop down a notch, then these brands' 2 stage var speed models. On AC the matching var speed condensers. There again, if you want to drop down, then high eff two stage models. On these recommendations, i would not consider anything less. I can give you specific model numbers if interested. Not a fan of Lennox. They think they are a top tier brand and they are in price. Dealer should take special precautions for heating and cooling bonus room. They can be very problematic if not insulated correctly. Air filter cabinet. Pay attention to adequate returns correctly sized and located for good airflow and comfort. Ductwork should be R8 insulation, metal supply and return trunk lines, flex OK for runs. Insist on a properly performed load calculation. Get it in writing and tell GC and HVAC dealer the design temperature you want used for in and outside, both cooling and heating. RH less than 50%. Correct controllers to be used and for your location, you want dehumidify on demand set up for AC cooling. IMO

Maybe this is one of the reasons the US Government has decided the minimum SEER rating in the southern states..... Then why would the US Government use the SEER rating as opposed to EER? You've answered your own question more or less. SEER and EER mean the same thing more or less, the only difference as stated earlier is the S which means seasonal. (So not only do you have daily changes in temperature, but also seasonal.) Weathermen have been tracking temperatures for a long time. This is how they know when a new high or low record occurs. These changes can then be taken to determine a good estimate as to the efficiency of the equipment while operating. They know based on set point of 75 degree indoor this area will have equipment run times of 2200 hours. (Houston area specific) This changes from one climate to another based on set points, ambient conditions etc. The US Government decides on minimum SEER ratings for a variety of reasons, one of which is to off set the load on the electrical grid. The south, especially Texas in particular has crazy growth rates compared to other northern climates. So as there is growth, the more efficient the equipment, the less strain there is on the electric grid (which is under immense strain during heat waves) brown outs, and rolling black outs would make for civic unrest and you'd have a mess on your hands like the world has never seen in a state that depends on air conditioning for upwards of 10 months of the year. Efficiency also keeps those electric bills down, so it's not a bad thing in that respect either. If you save $50 on your light bill, you spend that $50 some where else. Which in turn supports another part of the economy. Manufacturer's could fudge an EER number. For one you would need to know what constant temperature they selected for the EER number. Because remember this figure is determined by a 'constant temperature'. You could select 80 degrees. Everyone knows that at 80 degree ambient an air conditioner has a slightly higher capacity at lower temps. So what happens if the manufacturer changed it to 78 degrees. It would give you a slightly better EER. There are a few manufacturers that do not divulge these kinds of numbers. Why do you suppose that is? (to dupe the uninformed.) what other reason could there be? fill in the blank.