I just got a Harman installed in a 1700 sq split level ranch and love it. The P43 model is what we went with and it sits almost right up against the wall.

Space wise there is a 2” gap from the back of the unit to the drywall and sits on a 36x36 bluestone which meets manufacturer recommendations and thus CT regulations. There’s a 2” pipe that goes straight out and up the side wall about 3’ up on the outside. Total cost installed was just under $6400. Keeps the living room where it’s installed at around 72 f and the back rooms about 67 f on medium heat. I burn exactly one bag over a 20 hr period. This is roughly in 25-30 degree external temps so it’ll vary depending on weather and of course house insulation. Cost wise I am running a killawatt device to measure cost and it’s only showing about $20 month usage based on Eversource effective rate of about $.35 kWh which I think might be low. Pellet fuel runs about $210 per month give or take.

Overall I’m very pleased because I can keep the whole house liberally warmer at lower cost. My ROIC is roughly 4 years. After that I should be saving an extra $200 month.