I am considering a waterfurnace system for a new house in Connecticut. 4 ton with vertical closed loop NSH048, 2 wells total 540 feet. 3 zone system with HRV. The hose is new and insulated with icynene. I have been proposed a 15kw backup electric heat and 60 gallon electric water heater. I am being told that I may need 400 amp electrical service instead of 200 amp. Wondering if anyone has experience with this - seems like 200 amp should be more than enough, electrician says we are on the edge - looking for real world experience with Geo. No other strange loads - 2,600 SF house, hot tub, electric dryer, water well pump. Any other recommendations regarding system, options, questions to ask etc would be appreciated.