Solar Heater Up-date

Our Solar pop can heater is performing well on sunny days.  We are seeing temperatures coming out of it up to 102 degrees.  Sunny days our gas furnace is kicking in 1/3 as often as it does on a cloudy day.  This is giving us a drop in the amount of gas being used to heat our house this winter.  We have had only one fill of gas so far this year.  We like our home a bit cooler then most, we maintain a temp of 68 degrees on sunny days being heat mainly by the solar pop can heater.  Steve and I have seen days where the furnace has not kicked in for 5 hours with temperatures outside at 25 degrees.