I have an FPX 44 with a 4.3 cu foot firebox. It is heating two rooms. The room it is in is 20X30 with two of the walls being pretty much glass door with a glass transoms above the the doors. The other room is a ton of glass as well. Ceiling heights are around 15 feet. I have a ceiling fan running on high in that room. Been mixing locust and black birch that have seasoned for two years. Getting a ton of coals which are useless in this weather. I hate to say it, but this vortex has me feeling a little defeated. It is hard for me to get it past 67 and when I woke up this morning it was 58 in my house. That has never happened before. I was really looking forward to these cold snaps. I might have to do the unthinkable, flip the oil on for backup