Replacing oil furnace with heat pump, A contractor did manual j and it comes out to 2.5 ton, but the duct work he said supports only 2 ton, he proposed a lennox xp17 2 ton, with variable speed air handler(cbx32mv0 and 10kw(i think) strips. I plan to keep the temp at steady 67-71 in the winter. He says it will work fine, I am wondering if this sounds right? We have no room to add returns or supply easily. House is in Tacoma (near Seattle), WA.