Not for nothing I have noticed on the realy cold nights that my draft pics up some..for sure when it's windy and end up with a ton of coals. So I started using the damper. All the way closed but even then it's not sealing well and of course it has that hole..which is a good thing. Anyways it really did help on the coaling..slowed the out gassing down so the wood actually burnt down at a more linear rate with the out gassing. Down side house not as warm.