I have a 10 y/o trane xv80. It’s -3F in Chicago, and the furnace is struggling to keep 64F in the house, while set for 72. I don’t remember it being this bad in years past.
I had the furnace taken out this summer to repair a wall behind it, and it’s obvious from other signs that they did a poor job of reinstalling it. Given that, what are things that I can check that would result in poorer performance than years past? To be clear- it works, just not well enough or as well as in the past.