No problem. I think our biggest improvement were the windows (Vinyl, custom fit, Double Hung, Low E, Argon) , I replaced 23 this past summer, the house was already insulated (another big help), new door gaskets, sweeps, etc....I didn;t even notice it was in the single digits the other night. We also had space heaters (oil filled looking radiator type) upstairs in a couple rooms to help last winter. Haven't had to use them yet. It's nice being able to see out the windows without all the ice build up we had last winter with the single pane ones!!!
It's maintaining 68 (setpoint) with no problem. Actually a lot warmer than I thought, it was 60-62 last winter with the older Keystoker stove cranking 24/7. This Hyfire (w/Coaltrol) is only running 50-70% of max and a lot warmer in the house! Wife is Happy!! (and so am I!).