Have you considered a gas boiler that can provide you with both hot water and radiant heat? You can install a separate A/C system with ductwork. I assume by redundant systems you mean having both this and a heat pump, am I wrong? Have you considered a high-efficiency gas furnace and air conditioner setup (conventional gas/air)? I don't know very much about the Acadia, but I believe it's designed for very low temperature operation, which I'm not sure is really necessary but would likely be nice to have. What types of systems have you considered before getting into specifics? It would also help some members here by knowing your gas and electric rates per month.

Gas boiler for water & radiant heat is one option, but still requires ductwork for AC (redundant systems).High efficiency gas furnace & conventional AC advised by most so far. Quotes so far are widely divergent:

#1- 2 ZONE FORCED HOT AIR HEATING SYSTEM BY GAS WITH AIR CONDITIONING
2 Â "LENNOX" #G71MPP-36B-070 FURNACES
2 Â "LENNOX" 14 ACX024 A/C CONDENSERS
2 Â "TRION" AIR BEAR FILTERS
2 Â "LUX" PROGRAMMABLE THERMOSTATS
$16,400
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#2 - 175,000 95% Prestige mod boiler w/60 indirect hot water
2 3-ton Hydro Air units (2 zones)
$24,000
$99/unit condensor labor
Aprilaire 600A humidifier $575
Aprilaire 2400 air cleaner $550
***********************
2 York mod gas furnace w/ECM motor,#YP9C060B12MP11, w/3-ton coil,
2 York 2-ton, 2-stage condenser #CZH02411 (16.5 SEER, 13.5 EER)
2 Trior Air Bear filtration system
R8 sheet metal ductwork w/11 supply & 5 returns
$30,800

All opinions welcome. Thank you