AC Replacement Cost on the Treasure Coast: Salt-Air Rated vs Standard

The $5,800–$11,200 spread tracks system size, efficiency level, and installation scope. Smaller single-stage systems on straightforward swaps sit at the low end; larger homes, higher SEER2 ratings, and two-stage or variable equipment climb through the middle. The upper end typically includes duct corrections, electrical upgrades, or the coastal package — and Florida full-system replacement planning figures can reach $6,400–$13,000 when air handlers and ducts come along.

What the range should always include, at any price: the permit (Martin County requires one for AC installation), the load calculation, disposal of old equipment, commissioning with measured airflow and temperatures, and warranty registration. Quotes that exclude those line items aren't cheaper; they're incomplete.

Salt air corrodes condenser coils and cabinets four to eight times faster than inland conditions. Near the water — the river districts, the peninsula, the barrier island — a standard coil can shed fins and lose capacity in five to seven years; a factory-coated coastal unit resists that corrosion for its whole service life. The premium for coated coils and corrosion-resistant cabinets is modest against a premature $6,000–$10,000 do-over.

The honest rule: within a mile or so of open water, coastal-rated is the default specification, not an upgrade. Inland addresses get a real choice — though even a few miles inland, the salt breeze finds you on the prevailing wind days. We quote both tiers where the choice is genuine and only one where it isn't.

The DOE Southeast minimum is 14.3 SEER2 for split systems below 45,000 Btu/h (13.8 above), and everything above that minimum is a payback calculation: higher ratings cost more upfront and save runtime money across a nine-to-ten-month season. In our climate the payback runs faster than national averages — but only on correctly sized, correctly commissioned equipment.

The sizing half matters more than the rating half: an oversized high-SEER2 system short-cycles, dehumidifies poorly, and delivers the clammy-house complaint at premium prices. Manual J sizing, Manual S equipment matching, and commissioning data are what turn the efficiency premium into actual savings.

A comparable quote names the equipment model and efficiency, states the load-calculation method, itemizes duct/electrical/pad work, includes permit and inspection, and documents commissioning. Financing terms come with the APR and conditions in writing, not as a monthly-payment slogan. Three bids on that format compare cleanly; three bids on different formats compare badly.

The warning signs run the other direction: no load calculation, permits 'not needed,' commissioning skipped, and a price that's mysteriously $2,000 under the field. On the Treasure Coast, the cheapest bid on a waterfront home is usually the most expensive decade. Buy the scope, not the sticker.