David,I am in complete sympathy you, believe me. A quote "enuf is enuf but too much is plenty". I like you oil fired hot air system because I know in my heart of hearts that diesel oil fired can be translated into WASTE ENGINE OIL fired and that is free fuel. Has to be a way. 30K BTU will keep it hot after you insulate it and install more thermally efficient glass for sure. Only draw back is that it might take a while to get up to temp after a cold soak. Is you system a used military version, or a commercial?I am impressed with what you have been able to accomplish up there.John
20 lb now takes $18 to fill.My 100 lb went from $55 to $68 to fill. And that's just since last month.