solar vs. geothermal

 Please excuse a newbie question.  In a sunny place such as Denver,
which is a better idea - solar roof panels heating hot water that's
stored in an insulated basement tank, used to  supplement domestic hot
water and gas/forced air via a liquid-to-air heat exchanger, or a
"geothermal" ground source heat pump that might have to be supplemented
with electric heat as needed.  We've never felt the need for summer air
conditioning, so that aspect of the heat pump  might be a bonus or an
onus, depending on operating cost.  Our main question is which system
would provide the most economical winter heating in terms of system
cost, operating cost, and "payback" time.  We'll be in the house for at
least fifteen years.  Any observations, suggestions, opinions, are
welcome.  Fred in Denver

 

  I have read about both being done. The solar heats the soil and the
heat pump takes heat from the ground to heat the house. You can also
store heat energy in the ground during the summer for use in the fall.
If you think about the thermal mass of 1000 sq. ft. of earth 4 feet deep,
you can store a lot of heat there.