Mobile RV Rooftop AC Unit Replacement Across Florida

When Repair Stops Making Sense and Replacement Is the Right Call

The component hierarchy inside a rooftop unit runs roughly from cheapest to most expensive to fix: thermostat, control board, fan motor, capacitor, compressor. Every item except the last is serviceable at a cost that is clearly less than the price of a new unit. The compressor is the only part where the math routinely inverts. A compressor for a 13,500 BTU residential-style unit might cost $350 to $500 in parts alone, and that price does not include the labor to handle the refrigerant, the time to access the unit, or the fact that you are now putting an expensive part into a housing that has already absorbed a decade of Florida heat cycling, UV exposure, and salt air.

The practical test I use is straightforward. If the cost of the repair exceeds half the price of a new unit installed, and the existing unit is more than eight years old, replacement wins on every calculation - lower total cost, longer remaining useful life, and a warranty on the new unit rather than a warranty on a repair. Coaches sitting in Florida storage for extended periods tend to accelerate this timeline because units that run irregularly build up internal moisture and corrode internal contacts faster than units that cycle daily.

Will the New Unit Fit Your Existing Roof Opening

The short answer for virtually every coach built after the mid-1980s is yes. The industry converged on a 14-inch by 14-inch roof curb opening as a de facto standard, and Dometic, Coleman-Mach, and the other major manufacturers all build their current production units to that footprint. The curb is the raised flange that frames the opening in your roof; the unit sits on top of it and is sealed by a gasket between the unit base and the curb face. As long as the curb is intact and the opening dimensions are standard, any current production unit in the right BTU class drops in without modification.

The exceptions we encounter occasionally are early-production coaches with non-standard openings, and coaches where a previous owner or shop modified the opening to accept an aftermarket unit with a different footprint. We measure the opening during the service call before pulling the old unit, and if we find a non-standard dimension we order accordingly rather than showing up with the wrong unit and billing you for a wasted trip. That inspection is part of the service call charge, not an add-on.

What Brands We Install on Florida Coaches

For the 13,500 BTU class we stock and install the Dometic Penguin II and the Coleman-Mach 8. Both units have been in continuous production for long enough that aftermarket support is deep - capacitors, fan motors, control boards, and shrouds are available from multiple suppliers, which matters if something needs attention five years from now. The Penguin II in particular has a low-profile design that reduces wind resistance and is well suited to coaches that travel frequently, where a taller shroud takes more aerodynamic load at highway speeds. The Coleman-Mach 8 is a workhorse with a straightforward service layout and a track record in Florida's heat and humidity that goes back decades.

For coaches that need 15,000 BTU we fit the Dometic Blizzard and comparable units from the same performance tier. These are appropriate for slides-out coaches with larger interior square footage, or for owners who have found a 13,500 BTU unit marginal during peak Florida summer afternoons. The larger unit has a higher starting amperage draw, so before recommending it we confirm that the coach's shore power or generator capacity can support it without hard-start issues. Where that is a concern, we discuss a soft-start device as part of the same service visit.

How Long a Rooftop Replacement Takes at the Coach

A straightforward swap on a standard coach - one unit, a clean standard-dimension curb, and a ceiling assembly that does not need attention - typically takes two to three hours from the time the truck arrives. That covers removing the old unit, inspecting the curb for cracks or delamination, seating the new gasket, setting the new unit, connecting the wiring, and running the unit long enough to confirm the coach interior is dropping to temperature and all modes are responding correctly. We do not sign off and leave until the coach is cold.

Jobs that take longer are typically those where the roof curb shows cracks that need sealing before the new unit goes down, or where the ceiling assembly - the interior plenum and duct system that distributes air from the unit - needs repair or replacement. Ducted ceiling assemblies in older coaches can develop cracks and air leaks that are worth addressing while the unit is already off the roof, since the ceiling assembly is most accessible at that point. We quote any ceiling work separately and get approval before proceeding. The one thing that adds time we cannot fully control is access: a coach in a tight storage space or under a low tree canopy slows rooftop work, and we ask about that when you schedule.

What Happens to the Old Unit

We take the old unit with us. This is not optional and it is not negotiable, and the reason is straightforward: rooftop air conditioners contain refrigerant - typically R-22 in older units and R-410A in units manufactured in the last decade or so - that is a regulated substance under EPA Section 608. Leaving a unit at a campground dumpster or in a storage lot trash area creates a disposal problem for whoever finds it, and in some cases a liability issue for the coach owner. We are licensed to handle and recover refrigerant, and we manage the disposal through certified channels.

In practice this means the old unit leaves the job site on our truck and is processed through our disposal chain. There is no separate fee for this. If the old unit contains R-22, which is a phased-out refrigerant, we recover and handle it accordingly. If you have a specific question about what refrigerant your current unit uses, check the data plate on the unit shroud - it will list the refrigerant type and the factory charge weight, which also tells us what we are dealing with before we start the job.

Can You Install a Bigger Unit Than Your Current One

Within the standard BTU classes, yes. Moving from a 13,500 BTU unit to a 15,000 BTU unit uses the same 14-inch by 14-inch opening and no structural roof modification is required. The ceiling assembly may need to be swapped if the existing one is calibrated for the lower BTU output, but many ceiling assemblies are compatible across both BTU classes from the same manufacturer family. We check compatibility before ordering the new unit.

The real constraint on upsizing is electrical, not mechanical. A 15,000 BTU unit has a rated load current of approximately 15 to 16 amps and a starting surge that can hit 50 to 60 amps for that first fraction of a second. On a 50-amp shore power connection that is not an issue. On a 30-amp site, or running on a generator sized for a single AC unit, that surge can trip a breaker or cause a hard start. A soft-start device reduces the inrush current significantly - typically cutting it by 60 to 70 percent - and allows upsized units to run reliably on connections that would otherwise struggle. If you are considering moving up a BTU class, we will discuss the electrical picture honestly before ordering parts so there are no surprises on the day of the install.

Why Florida's Climate Accelerates the Replacement Decision

A rooftop unit on a Florida coach is under stress that a unit in a drier, cooler climate simply does not experience at the same rate. The UV index in South and Central Florida is among the highest in the continental United States, and direct exposure degrades the shroud plastic, gasket material, and the foam insulation inside the unit housing over a timeline measured in years, not decades. The humidity accelerates corrosion on electrical contacts and the condenser coil fins. Coastal salt air compounds the corrosion issue, particularly for coaches stored or used within a few miles of the ocean. And because Florida's summers run from roughly May through October with temperatures that make the coach unusable without air conditioning, these units log far more operating hours per year than units in northern states.

What this means practically is that a ten-year-old unit in Florida has often experienced the equivalent wear of a fifteen to eighteen-year-old unit in a milder climate. The decision point on replacement arrives earlier, and the case for installing a current-generation unit - which will have better efficiency ratings and a full manufacturer warranty - is more compelling. We see this calculation clearly after more than a decade of mobile RV service across Florida, and when we recommend replacement, it is because the numbers genuinely favor it over repair.

Pricing for Rooftop AC Replacement

Pricing below covers parts and labor for a standard replacement. The service call covers travel to your site and the opening inspection.