I'm looking to replace my old insert (1995 model), It's been good to me for 10 years. I'm looking at a new Classic Bay 1200i or P35i, both look small compared to my current stove but have a lot of BTUs. My old stove has great heat so I just want to make sure I at least get the same amount of heat without going overboard. I have 1 floor to heat and its just over 1,200 sf. I have read that you should buy the biggest you can afford when it comes to stoves and the 2 I'm looking at there is only $700 difference plus the cost of a new 4 inch pipe it I go with the P35I.