I picked up a solar thermal 30 tuber with 40 gall water tank on Ebay for $600 (see village gone green on youtube). This will be my third year of heating summer DHW with this unit for washing horses and now the house. Simple to plumb and provided you are not fussy about water temp to within a few degrees it saved me a ton. The morning excitement of is the shower going to be luke warm or scald the skin off me is enthralling. Now I have three working. Sadly, around here, it's not a winter option whatever Obummer and Chu tells you, April to Nov only. I am looking in the NY plumbing code for where garden water hoses are permitted
but as it's temporary who cares (insert ascerbic sting comment here)....... but it worx and is cheap.
No more HO, read my lips.... and soon no more propane