My cordwood is too green for me to get decent performance from my stove so I bought a couple packs of biobricks. I thought they burned fairly well....a little hot tho. Satisfied with the compressed sawdust concept, I got a load of Envi blocks in last week and have been burning a combination of pallet wood and the blocks (I will mix in some drier cordwood at some point). Personally I love the envi blocks for all night burns. In my stove I can keep 375-400 degrees for at least 7 hours with a load of 3 blocks. With last nights cold (-5F) I put in 4 blocks at 10PM, got the stove to 400F. This morning at 6:30 I had 350F with enough coals to light off 2 more blocks....longest burn I have ever gotten with my stove! When I first started using them I was real concerned about them running too hot, but my fears were unfounded. In fact I dont think the envi blocks are very well suited for getting super hot...warm up the cold house kind of fires going (biobricks were able to do this for me). For me pallet wood followed by the addition of 2-4 blocks gives me a hot fire followed by a cooler but longer burning sort of fire.