Delivered btu’s per hour

[Slimdusty]

check my math here please
1 pound of wood at 20% moisture contains about 7000 btu’s.

Let’s say my stove/setup is 65% efficiency.
So, for every pound of wood I put in my stove I get 4,550 btu’s into my home.

If I put a 20# load in and it burns for 5 hours, I am getting 18,200 btu’s per hour. Am I missing any variables here?

 

[stoveliker]

Correct.
65% is low, though.
And if your wood contains moisture (all wood does), you'll be using some of that to boil the water so it exhausts up the flue. But that may be accounted for in the 7000 BTU per lbs (as perfectly dry wood is around 8600 I think)

 

[Trevor Tahclep]

Chances are if your wood is properly seasoned you will also have many pieces below 20% as well.

 

[Slimdusty]

Correct.
65% is low, though.
And if your wood contains moisture (all wood does), you'll be using some of that to boil the water so it exhausts up the flue. But that may be accounted for in the 7000 BTU per lbs (as perfectly dry wood is around 8600 I think)

I used 65% to be on the conservative side. I believe the 7000 btu per pound figure already accounts for boiling off the water, like you mentioned. Ultimately what I am working towards is my BTU demands per day on average.