I will be replacing my oil fired boiler with geothermal (water furnace).  I will be using the system for heating radiant only (NO AC).  I have looked at a sidebar to do all of my Domestic Hot water also but man is it expensive $3,000.  The pay out versus just a standard electric water heater does not seem that great.  Any one else had this feeling.  right now a 50 gallon electric seems to make more sense than LP or on demand units.  any advice.  I have also looked at Solar however, One project at a time.

Thanks

It depends on how long you plan to stay in the home. If longer than about 5-8 years, then go with the heat pump domestic water. Otherwise, the next best thing for you will be an electric water heater.