I am not sure if other work is being performed. Here is what the quote says: We are pleased to submit to you an estimate and specifications for the installation of a Carrier 59TN6 Infinity two stage variable speed gas furnace with a Carrier 25HCB6 Performance 16SEER two stage heat pump Hybrid system to be installed in your home. Recover refrigerant as required by law. Remove and junk existing gas furnace, air conditioner and thermostat. Furnish and install one #59TN6A100E21-22 Carrier high efficiency Infinity series two stage/variable speed furnace with one #KGANP5201VSP Natural to Propane conversion kit and one #25HBC648 Carrier Puron high efficiency Performance series two stage heat pump with one #CNPVP4821ATA Carrier tin plated cased evaporator coil. The furnace has a 96.0% AFUE efficiency rating and a 100,000 Btuh input capacity. The heat pump has a 47,500 Btuh nominal cooling capacity high stage and 39,000 in low and a 16.0 SEER rating. New furnace to sit in same location as that of existing with a new return air drop, filter rack with hinged door, plenum and necessary sheet metal fittings to reconnect to the existing supply and return ductwork. Reconnect to the existing electric furnace circuit with a new switch and box. Reconnect to the existing gas line. PVC venting to be reconnected to existing. New condensate drain line to the floor drain with a new trap and clean out. New heat pump to be installed in same location as that of the existing. Furnish and install new outside fused disconnect as per Carrier and code requirements. Purge with nitrogen and reconnect to the existing refrigerant lines from the new indoor coil to the new outdoor unit. Furnish and install one #STAT-TP-PRH Performance programmable Thermidistat. Complete with necessary taxes, labor, wiring, and materials. COST Furnish and install the complete Infinity/Performance Hybrid HVAC system as described for Ten Thousand Eight Hundred and Ninety ($11,765.00) Dollars. This system qualifies for $200.00 Duke Energy rebate and a $150.00 Carrier rebate. OPTIONS Add one Carrier #GAPAAX1625 Infinity air purifier for an additional $1,550.00. This also qualifies for a $150.00 Carrier rebate. Net $1,400.00. I don't mind paying a fair price, but I don't want to be taken advantage of.

The overhang issue is a big one. That along with orientation can mean the difference between not using a/c or using a lot of a/c (particularly in your climate) - particularly with 96/60 and low humidity. The unusual thing about that is that traditional construction/design keeps a house cool prior to a/c. I would presume they did it with mass in adobe construction. High desert is so ideal for mass and solar design. Manual Js are somewhat complicated but going line by line you can usually make sense of them. There is usually a summary page that includes the Heat gain and losses per item - somthing like 20,000 btuh from walls, 10,000 btuh from windows. There are measurements of walls, roof/floor, window sizes. You can't ensure that the calcs are correct but you can check the inputs. The dead ringer is infiltration - find that number and see how your house is described. This is the easiest fudge factor in my mind. They often use average - go and read what average is supposed to be - it is not new house average, it is overall average. The a/c load is possibly correct. Windows to the west can let in a lot of btus. Do you have a wall of windows to the west for a view?

Thanks very much, tigerdunes. 3 tons makes sense to us because much of the upstairs cooling ends up downstairs, with the result that downstairs remains cool year round despite the dozen downstairs skylights (and six upstairs). We used to have a 5T AC on the downstairs system as well, but when it died we didn't notice downstairs getting any warmer and realized that the 3T upstairs must be cooling downstairs via the staircase, even more effectively than upstairs ironically. So really the upstairs AC is cooling a 3600 sf house (plus 900 sf basement which however remains naturally cool). Cooling efficiency for the upstairs system is important to us because (a) it spends far more time cooling than heating; (b) matter of principle: reduce our consumption footprint; (c) lower operating cost over next 20 years (for us and any subsequent owners of the house). System being replaced: 1988 Carrier 3 ton D&N (Day & Night) Heat: D&N 395BAW036060ABJA (3 burners, 71,000 Btuh in) Cond: D&N 568EJX036000AGAA (3 ton) Evap: label inaccessible Downstairs system that we're sticking with for now Heat: D&N 395BAW060120ABJA (6 burners, 143,000 Btuh in) Cond: D&N 568EBX060000AGAA (5 ton, long dead) Evap: BDP 518CXX057000BACA

Our concerns: While I realize we live in the South, we love the heat. I keep the AC on 78 during the day and work from home. I don't like it when the air is running. We have been told the 2 stage will be on more and blow out less and not bother me. Not sure if this is true?? Air conditioning as well as heating is something that has tiers of energy performance. This energy performance has to do with efficiency that in some cases saves you operating costs. The con in this arrangement is that you must be running the equipment. (If the equipment is off there is no energy drain... in that sense it doesn't matter what rated efficiency the equipment is.) Because your preference is 78 changes the arrangement. The more efficient the equipment the more the set up will cost, the less you operate the equipment the less likely it is to save you much in terms of operational costs. Minimum efficiency ratings for your area is 14 SEER. These are all single speed machines. However, since July 2019 the furnace blower efficiency standards have been raised to require no less than an ECM blower motor to raise efficiency. Some manufacturer's may still have the older PSC style blowers and probably at a discount. Because of your preference of a higher indoor temperature / how you prefer to operate the equipment it's not necessarily a bad idea to drop down to 14 SEER AC and a PSC blower motor / single stage gas furnace. If you can't find a PSC blower (multi tap single speed) furnace / the ECM motor would raise the efficiency of the AC to 15 SEER. You will most likely have to 'shop around' find a HVAC contractor that is willing to listen to what you want... as opposed to what they would prefer to install. I service the Katy, Texas area.