Ok as some of you know I'm new to wood burning. I had my small 1.3 cf wood insert installed and it did not have a block off plate. What was I missing not having a block off plate? Im going from 1.3 cf to 2.3 cf for longer burn times. This install I will be adding a block off plate with Roxul , and probably adding and sealing Roxul in the old fire place firebox around the insert because I have heard of others doing this on this site. My little 1.3 did perform well until sub zero temps. I have 1700 sq and it did keep the house around 70 which is good. Any help would be appreciated, would adding a block off plate to the 1.3 make a difference?