My new Harman P43 has been running for a whole 2 hours now. Its on constant burn, feed 4, temp 5. Putting out good temp. My house is not quite 1900 sq ft with 20 ft ceilings in living room. Two upstairs bedrooms and a bath. Master is on bottom floor with a large bath tucked away,kind of isolated. Have not felt any heat back there yet but rest of house is getting toasty. I knew going into this that a P43 would be on the small side for this house but it was all the wife would let me budget for. I guess better than nothing. Few more hours should tell me how well it will heat the house. 27 degrees out now getting down to 17 tonight. This is a heat wave compared to what it was last 2 days.