Lean Left

Anyone have any clue as to the pros and cons of the following:

- an 80% AFUE gas furnace that’s two-stage with a variable speed fan
- a 95% AFUE gas furance that’s single-stage with a fixed speed fan

My understanding — which could easily be deeply, deeply flawed — is that the former will be more comfortable, but somewhat less energy efficient, and that the difference in energy efficiency won’t be as big as the numbers imply, because the number refers to while the unit is in use at capacity, and the former unit will be in use at capacity less frequently.

If anyone knows better / different, now would be a great time to let me know.