Choosing a system is mostly a sizing question, and sizing is where most Florida installations go wrong. Get the capacity right and a mid-range system will outperform a premium one that somebody picked off a square-footage chart. Get it wrong and nothing rescues the result. Not the efficiency rating, not the warranty, not the badge on the cabinet. That ordering surprises homeowners, who arrive at this decision expecting a brand comparison and discover that the brand is the least consequential of the four variables on the page.
Sizing is the part that matters
Bigger is not better, and in Florida it is actively worse. An oversized system cools the air fast, satisfies the thermostat and shuts off before it has run long enough to pull moisture out of the house. You end up cool and clammy. Most people describe that as the air feeling heavy, or as the house smelling musty by August, and almost nobody connects it to the tonnage on the nameplate.
Proper sizing comes from a Manual J load calculation. That calculation accounts for square footage, ceiling heights, window area and which direction those windows face, insulation levels, shading, air leakage and duct condition. A west-facing wall of glass in Brandon changes the answer. So does a house that was reroofed with radiant barrier last year. Anyone quoting tonnage from floor area alone is guessing, and the guess runs high almost every time, because a contractor who undersizes gets callbacks and a contractor who oversizes rarely gets blamed. We took that apart in more detail in what size air conditioner you actually need in Florida.
Ask whether a load calculation is included before you accept any quote.
One more wrinkle applies to remodeled houses. If you added impact windows, blown in attic insulation, or closed in a carport since the last system went in, the load your house presents today is smaller than the load it presented then. Matching the old tonnage because it is what was there before locks in an oversizing problem you paid good money to eliminate.
System types worth considering here
Four configurations cover nearly every Tampa Bay home, and the right one is usually decided by what the house already has rather than by preference.
- Central split system. Outdoor condenser, indoor air handler, one thermostat. The default for a house with usable ductwork.
- Heat pump. The same hardware running in reverse to produce heat. Our winters are mild enough that a heat pump handles them comfortably, and it beats running electric strip heat on the handful of genuinely cold mornings we get. If nobody has explained the difference to you, how heat pumps work here is worth ten minutes.
- Ductless mini-split. Built for additions, converted garages and houses that never had ducts. The inverter compressor modulates instead of cycling, which makes it unusually good at humidity control.
- Packaged unit. Every component in one outdoor cabinet. Common on slab homes and older Pinellas houses where there is simply nowhere indoors to put an air handler.
How much efficiency to buy
Florida sits in the DOE Southeast region, so our legal minimum is higher than most of the country: 14.3 SEER2 for systems under 45,000 BTU and 13.8 SEER2 from 45,000 to 65,000 BTU, in force since January 1, 2023. You cannot legally buy below that here. Above the floor, returns are real but they flatten out, and the flattening happens sooner than the sales literature suggests.
Stepping from the minimum to the middle of the range is usually worth it in a climate that runs cooling eight or nine months a year. Two reasons justify going to the top of the range, and neither is the efficiency number. First, a house that runs its system nearly around the clock, where small percentage gains compound into something visible on the bill. Second, and more important, high-efficiency equipment is nearly always variable-speed, and variable-speed operation is the best humidity tool sold. Humidity, not temperature, is the comfort problem most Florida homeowners have.
Buy the variable speed for the humidity. Treat the efficiency rating as a bonus.
Do not ignore the ductwork
Leakage of 20 to 30 percent is ordinary in older Florida homes, and attic ducts in this state sit in 120 to 130 degree air all summer. Supply-side leaks throw away conditioned air you already paid to produce, straight into a space nobody occupies. Return-side leaks are worse. They pull 130 degree attic air into the system and then ask the coil to cool it, which is how a house ends up running the condenser continuously in September while never quite reaching setpoint.
A new condenser bolted onto that arrangement will not deliver its rated performance, and no efficiency rating on the box changes the arithmetic. Which is why the right sequence puts a ductwork assessment inside the quote, not after the install, when correcting it becomes a second job and a second invoice.
What to ask every contractor
Ask all of them the same questions. Quotes only become comparable once you know they describe the same work.
- Will you perform a Manual J load calculation, or size this from square footage?
- What condition is the ductwork in, and is any correction included in this number?
- Which refrigerant does the quoted equipment use? Most new residential systems are moving to R-454B, with some brands on R-32.
- Are the permit and the county inspection part of this price? A quote without them is not cheaper, it is incomplete, and you will discover the difference at closing when a buyer's inspector asks for permit records that do not exist.
- Whose license number is the job permitted under?
- Within a mile of salt water, are coated coils specified?
That last one deserves a note. The first mile or so from salt water typically earns a C4 rating or higher, high corrosivity, on the ISO 9223 scale, and coil failure along the coast tracks that rating with depressing accuracy. A homeowner in Redington Shores and a homeowner in Valrico are not buying the same machine, whatever the model number says.
Where the decision usually lands
For most Tampa Bay homes the answer is a correctly sized heat pump, mid-to-upper efficiency, on ductwork that has been sealed or replaced where it needed it, installed under a permit by someone whose license is on the paperwork. That is an unglamorous answer. It is also the one that produces a house that holds 75 degrees and 50 percent relative humidity without drama for fifteen years.
We install and service Carrier, Goodman, Rheem, LG, Midea, Trane, Daikin, Mitsubishi and Lennox. If you want the process laid out step by step before anyone comes to the house, our installation process covers it, and an estimate starts with the load calculation rather than with a catalog.
