Start with conditions, not a product
Builder-grade equipment from the 1990s and 2000s was often sized to a spec sheet, not to the actual house — replacement is the moment to correct duct leakage, weak returns, and capacity that never matched the load.
Build a complete scope
- A load calculation for this house, not a swap of the existing tonnage
- Duct condition and leakage in unconditioned attic space
- How upper and lower floors are zoned, which drives most comfort complaints
- Humidity control, since oversizing satisfies temperature and not moisture
- Electrical work, permits, commissioning readings, and warranty registration
Cary context
Cary's subdivisions were built in waves over four decades, so a house and its original HVAC system are often much closer to their design life than the neighborhood's overall age suggests.