I have a 4600 sf house just outside Hartford ct that has two Lennox A/C units (10acb36 and 42) and oil furnaces. The 3 ton a/c compressor, serving the downstairs, has seized and since it is 14 years old I'm leaning towards replacing with a new unit (rather than just a dry-charge replacement with uncertain coil or other issues).

One firm has suggested we consider a heat-pump (XP17 - though I think XP14 might make more sense with existing furnace?) and I was wondering how much utility I might get by having just the one heat-pump with my oil as both back-up on that unit (right?) and upstairs serviced with still working 10acb42/furnace.

I hope I've given sufficient info for opinions. I might ad that my wife likes it 72-74 degrees all year round and keeps widows closed due to allergies. Also add that I have 4 fireplaces that i need to do a better job of sealing during the winter.

Thanks for thoughts and clarifying questions.