[Stoves] Water heating fuel efficiency formula

[Lanny Henson]

I need the formula or spread sheet, for fuel efficiency, for heating water, 
considering the moisture content of wood,  and using red oak as fuel. Not a 
water boiling test with simmering,  just a water heating test.

I have searched and there is a lot of discussion about water boiling test 
but I can't find the actual formula or spreadsheet.

I once knew how to do it using BTU and pounds but I need to get metric!

Pardon my stove blather but I am doing a lot of sitting around lately until 
my leg heals.

Lanny