went with it in our shop 40X64
1000 gal propane tank in the ground using one of those wall hung baxi boilers set at 50 deg. the temp is always around 55-58.
we fill the tank every second year. (could get 3)
filled it this year and it took 580 gals.
two years ago it took 500 to fill it to 85 percent.
about $350.00/year
