I have first-hand experience of how rough elm is to split and burn (tried it in our woodstove last winter and I had to run the stove wide open). We're getting a Thermo Control boiler for this winter and I'm wondering if the low BTU value of elm is going to be a problem. I've got a 150 yr. old giant lying on the ground about 20 yards from my woodpile, and it would be a shame to waste it.