I finally pulled the trigger and had geothermal installed in our home. It definitely took a leap of faith and so far everything has been working well though its only been about 1 month. Our house is old (200+) but with an addition and these internals were the main thing that needed to be replaced to keep it around for the next century. With all of the rebates and tax credits it worked out to be an even better deal as a historic property. House: 6000+ sq feet above ground 3000 sq ft masonry 2 levels +finished attic + unfinished basement with ductwork built 1760 3000 sq ft stucco 2 levels, unfinished attic, unfinished basement with ductwork built 2000 The new system: 5 -vertical wells were completed 400' each 3 -4 ton CM tranquility 30 units ( 1 package, 2 split) 3- new water heaters connected to the desuperheaters. The old system: 2 -4 ton AC units 1- 3.5 ton AC unit 1 - 2 ton Mini Split 1- 1 ton window AC unit 3 - water heaters Radiant heat Oil Boiler more than 50 years old 13 zones 26% federal tax credit 20% historic property state tax credit 25% county property tax credit for historic property 3000 MD energy administration Grant 4500 BGE tax rebate A good deal in the end.