Ok, the basics: 3300sqft farmhouse south of rochester, ny currently using an 80% efficient forced air system with no air conditioning (which is a big draw for me with goethermal). I have attempted the manual J myself as has one of the two companies, both came out around 100kBTU but they are both likely high because 1)I don't know what insulation is in the walls, so we assume none, 2) we checked insulation in the attic at one point (floorboards over the insulation) and the cavity was only 3/4 full, so we assume the entire attic floor cavity is only 3/4 full (but no confirmation). However, all is not lost. I can tell you I used 1000 gallons of oil this winter, and based off of degree days I would be somewhere between 50k-60k BTU at a 70F offset (so lets assume 60kBTU). Quote 1) Waterfurnace 7 series 5 ton "6 Ton Horizontal Loop" Non-Pressurized flow center Touchscreen Thermostat Desuperheater 52 gallon Storage Tank 52 gallon State Select Electric Hot Water Tank (my current tank is at the end of the life, might as well be replaced now) Modify ductwork supply/return plenum. Install new return plenum with welding in turning vanes to increase heat transfer and filtration capacity 10kWh Aux Heat Price: $26k (before tax credit) Quote 2) Waterfurnace 7 series 4 ton Vertical Bore Pressurized flow center Touchscreen Thermostat Desuperheater 40 gallon Vaughn S-Series Electric Water Heater 40 gallon Vaughn Aqua Boost Storage Tank High Efficiency AprilAire 2410 Adapt to the current supply and return trunk, line the plenum and drop with acoustical liner, correct all ductwork as needed, balance the duct work to the best of our ability. 10kWh Aux Heat Price: $31k (before tax credit) Initially the Quote 2 price was $7k higher using a 5 ton based off of the 100kBTU manual J before I provided that company with my oil consumption data (in which they stated "Oil Consumption Method" put my heat load at 45kBTU, and the "Bin Method" heat load at 58kBTU for a 67F offset). Also, quote 1 did not provide me with information regarding how they sized they system, but based on my data (50-60kBTU) it fell in the ballpark. So, quote 2 wants to drop down to a 4 ton 7 series versus quote 1 at the 5 ton. Any thoughts as to how that would negatively affect me? How much would I be using aux heat? I have seen $2k-$4k thrown around per ton (for adding/subtracting from a system), so that would imply option 2, being $5k more expensive, but a ton smaller, has a net cost difference of $7k-9k (if standardizing to the same size system) right? Also, quote 2 wants to use Vaughn water heaters/tanks. Based on what I have found they are pricey. What benefits do the Vaughn tanks have versus whatever homedepot offers or a marathon tank (marathons look to be around the same price as a Vaughn). In terms of water quality, my water is naturally hard (16 grains/gallon) and has iron (1.2ppm). I have a softener that is correcting those things, would high mineral content or softened water affect the stone lining of the Vaughns? Are they worth the cost? Would the pressurized vertical bore loop with Vaughn tanks cause the $5k difference in price? are they work the $5k difference in price? Quote 2 comes from a company that works with the state to provide a low interest financing option, so I would prefer to go with the company from option 2 (if the state wants to subsidize paying for my geothermal why not). But at $5k (and with a smaller unit) I am assuming it is not the better option. Final question. quote 2 also offered a similar quote (lets call it 2a) with the only change being they would use a 5 series 5 ton. for $28k, which gets them closer to the ballpark of quote 1. So, is a 4 ton 7 series work $3k more than a 5 ton 5 series? And how much better is the 7 series? Are the 4 ton 7 series and 5 ton 5 series similar in capacity? I know this was a long first post, and I apologize, I have been lurking the board for awhile and I thought I knew enough now to make my own decision. But I need help. Please note, I think I am smarter than I am, so I will attempt to answer any question, but it is quite possible I have no clue what I am talking about. So, it might be in your best interest to treat me like a 4 year old when asking questions, if not, you might not get the appropriate answer to your question.