My parent's have always loved their system and they use it for hot water and also for heating. Although solar will not suffice as a stand-alone heating system (cloudy days, etc.), it heats their house VERY well (warmer than I can stand...and 'free'
) most of the time (supplemented with a wood stove in the basement, and a fire place insert), and the hot water out of the tap will typically scald you if you aren't careful. I'd have to ask my dad about actual temps, but it's generally way hotter than the setting on a typical hot water heater. Just FYI, in addition to the three 120 gallon tanks, their system also has 'regular' 80 gal. hot water heater in the loop for boosting the temp if necessary.