Yes. Replacing an older HVAC system with an R454B heat pump does not automatically mean that the entire duct network must also be replaced.

Ductwork is part of the air-distribution system and can often remain in service if it is suitable for the new equipment.

What should be checked before reusing ducts?

The existing duct dimensions, airflow capacity, leakage, insulation, physical condition, supply and return configuration and total pressure loss should be evaluated.

What if the new heat pump requires more airflow?

If the new system requires more airflow than the existing ducts can carry without excessive velocity or static pressure, selected ducts, returns or grilles may need to be enlarged or modified.

Is refrigerant type related to duct compatibility?

Not directly. The refrigerant circuit and air-distribution system are different parts of the HVAC installation.

The main question for the ductwork is whether it can properly handle the airflow required by the new equipment.