Old unit out, correctly sized unit in, ductwork reused. The install is the part that decides whether a good system performs like one.
Equipment gets the attention and the install decides the outcome. A correctly sized system that is charged properly and breathing through ductwork that can actually carry the air will outlast a bigger, more expensive unit that was dropped in and turned on.
That is most of what separates a ten-year system from a four-year one, and none of it is visible in a brochure.
