Pittsburgh note
Pittsburgh’s long heating season makes AFUE meaningful, but distribution quality and combustion safety still decide whether a high-efficiency appliance feels like a good investment.
AFUE is not comfort
A high-AFUE furnace can still create cold rooms if returns are weak or ducts are leaky. Efficiency ratings do not fix delivery problems in older homes.
When to pair AFUE with a bigger decision
If the AC is aging too, furnace replacement is often the moment to compare dual fuel or heat-pump paths instead of locking in another single-fuel decade by default.