What HVAC replacement really costs in Miami-Dade County, plus a free cost calculator.

Typical HVAC replacement cost by system size

These are planning ranges for a full split-system replacement, condenser plus air handler and coil, sized correctly for a Miami-Dade home rather than just matched to whatever tonnage was there before. Use the cost calculator with your square footage and ZIP code for a tighter number, then check any quote against it.

• 2-ton system (up to about 1,000 sq ft): roughly $5,500 to $9,000. Common in smaller Hialeah bungalows, additions, and condo-style units where the conditioned space is limited.
• 3-ton system (roughly 1,000 to 1,600 sq ft): roughly $7,000 to $11,500. The most common size for older single-story Kendall and Hialeah homes with one central air handler.
• 4-ton system (roughly 1,600 to 2,400 sq ft): roughly $9,000 to $14,500. Typical for larger Kendall and Coral Gables single-family homes, and for two-story houses split across two zones.
• 5-ton system (2,400 sq ft and up): roughly $11,500 to $18,000. More common on the larger lots in Homestead and in bigger Coral Gables and Kendall properties, sometimes split into two smaller zoned systems instead of one large unit.

A meaningful share of older housing in Hialeah and parts of the City of Miami was never built with a full duct system. Retrofitting ducts into a home that has none, or replacing a failing package unit on a slab home with no attic access, both add real labor cost on top of the equipment ranges above.

Correct sizing matters more here than almost anywhere else

Miami-Dade's climate is defined less by peak temperature than by how much moisture the air holds nearly every day of the year. A cooling system does two jobs at once: it lowers the temperature (sensible load) and it pulls moisture out of the air (latent load). An oversized system satisfies the thermostat quickly, shuts off, and runs again a few minutes later, a pattern called short-cycling. Each short cycle cools the air but never runs long enough to properly dehumidify it, so the house feels cold and clammy at the same time, and that trapped humidity is exactly what feeds mold growth inside ductwork, behind drywall, and in closets.

The honest way to size a replacement is a Manual J load calculation based on the specific home, insulation, window area, and orientation, not simply installing whatever tonnage was there before. A contractor who quotes a system size without asking about square footage, insulation, duct condition, and window exposure is guessing, and in a county where the AC effectively never gets a season off, that guess compounds every single day it runs oversized.

Salt air and coastal corrosion on the condenser coil

Miami-Dade includes barrier islands and waterfront neighborhoods along Biscayne Bay in addition to inland communities like Kendall and Homestead, and salt-laden air corrodes an unprotected aluminum condenser coil noticeably faster near the water. Homes in coastal and bayfront pockets of Coral Gables and the City of Miami see coil failure well ahead of the equipment's rated lifespan when a standard coil is installed outdoors without protection.

Manufacturers sell coated or e-coated coils, and some offer factory-corrosion-resistant condenser lines, specifically for this exposure. If your property sits within a few miles of Biscayne Bay or the ocean, ask whether the quoted condenser has a coastal coil option and whether it changes the equipment price, since it is usually a modest upcharge compared to replacing a bare coil again in five to seven years instead of the fifteen-plus years a protected coil can reach.

SEER2 minimums and the 2025 refrigerant transition

Two federal changes affect what a Miami-Dade replacement quote should look like right now. First, since 2023 the Southeast region, which includes all of Florida, has required a minimum efficiency of 15 SEER2 for split-system air conditioners under 45,000 BTU/h, a step up from the older SEER rating scale used before. A quote for anything below that minimum on a standard split system is not a legal installation in Miami-Dade, regardless of the price.

Second, as of 2025 new residential AC and heat pump equipment is transitioning away from R-410A refrigerant toward lower-impact refrigerants such as R-454B, under the federal AIM Act phasedown schedule. R-410A systems already installed can still be serviced, but virgin R-410A supply is shrinking and getting more expensive as production caps tighten, which is one reason a repair on an aging R-410A system sometimes now costs close to what a partial replacement would. New systems built for the newer refrigerants use different components and, in some cases, different safety and installation requirements, so ask directly which refrigerant a quoted system uses and whether your installer is certified to handle it.

Hurricane exposure, permits, and AHRI-matched equipment

An outdoor condensing unit is a piece of equipment sitting outside in a county that gets direct hurricane strikes. A compliant Miami-Dade installation should include a properly anchored, wind-rated pad with hurricane tie-down straps rated for the local wind zone, a weatherproof disconnect box, and ideally point-of-use surge protection for the compressor and control board given how frequently Florida's summer storms produce lightning strikes near residential equipment.

Permitting in Miami-Dade is not centralized. More than 30 municipalities run their own building departments, and unincorporated areas permit through Miami-Dade RER, the same structure that governs roofing permits in the county. A full system replacement generally requires a mechanical permit and a rough-in plus final inspection, and code officials increasingly ask for an AHRI Certificate of Product Ratings showing the condenser, coil, and air handler are a certified matched combination. A mismatched combination, common when a contractor swaps only the outdoor unit and reuses an old coil, will not perform at its rated SEER2 and can fail inspection or void the manufacturer's warranty outright.

Miami-Dade cities and what tends to differ locally

• Miami: A mix of older bungalows with undersized or absent ductwork, mid-rise and high-rise condos where HVAC is often a packaged terminal or split system handled unit-by-unit, and waterfront pockets near Biscayne Bay where coastal coil protection is worth the upcharge.
• Hialeah: Dense, older single-family and small multifamily housing stock, frequently on slab with no attic, where a package unit replacement or duct retrofit adds real labor cost beyond the base equipment price.
• Kendall: Large 1970s-through-1990s suburban housing stock, mostly with ducted split systems now old enough that oversized replacements installed on a "like for like" basis are common and worth double-checking with a real load calculation.
• Homestead: Larger lots and newer average housing age from post-Hurricane Andrew rebuilding, with bigger homes more likely to need a 5-ton system or a two-zone setup.
• Coral Gables: Historic district design review can restrict where outdoor condenser units and line sets are visible from the street, and bayfront and canal-adjacent properties see faster coil corrosion, making a coastal-rated coil a reasonable ask.

Frequently asked questions

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