Start with conditions, not a product
Large newer homes with long duct runs and multiple zones are prone to leakage and humidity imbalance that a single filter change won't solve.
Build a complete scope
- What is actually driving the symptom
- How floors, finishes, and landscaping get protected
- Material compatibility across a larger floor plan
- Permits, testing, and cleanup
- Warranty terms and the change-order process
Johns Creek context
The housing here creates a specific and very common comfort complaint: large late-twentieth-century houses, frequently two and three stories, served by systems that were sized generously but zoned poorly -- which is why upstairs rooms run warm while the main floor is cold, and why simply adding capacity usually makes it worse rather than better. Georgia's climate compounds it, because the real work in a humid summer is removing moisture, and an oversized system satisfies the thermostat quickly, shuts off before it has dehumidified, and leaves a house that is cool and clammy. The other local factor is where the equipment lives. Air handlers and ductwork in these houses are typically in unconditioned attic space, where summer temperatures are punishing and duct leakage costs far more than the same leakage would in a conditioned basement -- so duct condition and sealing frequently matter more than the equipment on the quote.