I had recently asked for some advice on how big of stove I need for my home, but thought I would try again, since I now have more useful information on my situation. I have a 10 year old home. 8ft ceilings, open floor plan, and 2x6 construction. The main floor is 1000 sq ft. and the upstairs is around 800 sq ft. We keep three of the guest rooms closed resulting in around 400 sq ft of used space on the second floor. We have used around 140 gallons of oil since we filled up around 70 days ago. Temps have averaged around 32 in the day and 23 at night. I am considering the XXV and P61A, but the price of the P43 is attractive. Would I be able to get away with a P43? Thanks for any help.