Hi - We're seriously considering installing hydronic / radiant floor heat in our older home (~100yrs old, ~2,000 sq feet, located in northern Ohio)) this summer for next winter. First floor is easy, as the joists are exposed and we can run the pex under the floor. The long term plan will be to put solar panels on the side of our house to heat the water (we have plenty of room as we live in the country).
The question we have is what type of water heater would work best? One company that sells hydronic systems markets American Water Heater's Polaris, a 50 gal. gas tank, input BTU between 150,000 - 199,000 btu/hr, and a GPH recovery 90' rise of about 200 - total cost for this heater is over $3,000! Where as A. O. Smith has the ProMax SL system for recirculating hot water loop systems - with tanks up to 74 gallons. However, their input BTU is about 75,100 and recovery at 90' rise is about 81 gallons.
Is the Polaris overkill? Does anyone have a hydronic system out there, and what size tank do you use?