RV air conditioner dripping water inside: the leak that is not a roof leak

Water dripping from the rooftop air conditioner onto the bed is one of the most common calls we take in Sebring from June to September, and the answer is usually cheap: a clogged condensate pan, $200 to $400 to clean. The second suspect is a compressed AC gasket, $200 to $450. A real roof leak is possible but it is the third thing we check, not the first. Trip fee $75 to $150, diagnosis before any quote.

Check this first (five minutes)

When does it drip? Run the AC for a few hours on a dry, humid afternoon. If it drips with no rain, it is the pan. If it only drips during or after rain, it is the gasket or the roof.
Where does it drip? From the interior AC assembly itself, out of the grille or the edges of the ceiling plenum: pan or gasket. From the ceiling panel a foot or more away from the unit: more likely sealant or a seam.
Set the fan to high. A pan that is close to overflowing sometimes drips only when the fan is on low and the evaporator is coldest. Not diagnostic on its own, but a clue.
If you can safely reach the roof, pull the shroud. Standing water in the pan with green or black growth, and drain ports you cannot see daylight through, is your answer.
Turn the unit off until it is dealt with. Water through the ceiling assembly finds the control board and the 120V wiring, and that turns a cleaning into a board.

What is usually wrong

What you observe	Likely cause	Fix and cost
Drips after hours of running, no rain needed	Condensate pan and drains clogged	Pan and drain clean, $200 to $400
Drips during rain, from the unit itself	AC gasket compressed	Gasket replacement, $200 to $450
Drips during rain, from the ceiling nearby	Lap sealant at the AC or a vent	Spot reseal, $150 to $400
Drips only when parked nose-down	Rig off level, pan draining the wrong way	Level the rig, then clean the pan
Drips and the unit has stopped cooling	Pan overflow has reached the board, or a frozen evaporator	Board $250 to $600; thaw and clean
Ceiling panel soft or stained brown	Water has been coming through for weeks	Clean or reseal, plus interior panel work

Same figures as the pricing page, with labor at $125 to $190/hr inside those ranges.

Why this is a Highlands County specialty

A rooftop RV air conditioner cools by running warm, wet air across a cold evaporator coil. Water condenses on the coil, drips into a pan beneath it, and leaves through drain ports onto the roof. In a dry climate the pan sees a cup of water a day. Here, with July averaging 79 percent relative humidity and a muggy season that runs from late April to mid-November, the same unit pulls gallons out of the air every day for seven months.

A warm, dark, permanently wet pan is an algae farm. The growth builds up on the bottom of the pan, breaks loose, and plugs the drain ports, which on most units are small. Pollen and leaf litter pulled in through the condenser help it along, especially on shaded sites like the wooded ones at Peace River or under the oaks at the Okeechobee parks. Once the ports are plugged the pan fills, and the overflow has nowhere to go but down through the ceiling assembly, which is why the wet spot is on the mattress under the unit.

The gasket is the second Florida mechanism. The unit seals to the roof with a thick foam gasket, not sealant, compressed by the bolts that hold the ceiling assembly up. Over the years it takes a set, and in a climate where the roof is wet from June to September, a gasket that has lost its squeeze lets rain in around the unit. The stain looks identical to a pan overflow, which is why timing (dry afternoon versus rainstorm) is the first question we ask.

What the fix involves

For the pan: shroud off, pan and evaporator area cleaned of growth, both drain ports cleared and flushed, and a check that the pan drains the right direction with the rig at its parked level. We clean the coils while the shroud is off, because a unit with a fouled pan has fouled coils, and a coil clean is what keeps it from happening again next month. For the gasket: the interior assembly comes down, the unit lifts, a new gasket goes on, and the assembly bolts back up to the right compression. Both are one-visit jobs from the truck.

Once a year, before the June rains, is the right interval for a pan and coil clean on any rooftop unit in this county. It is the single best maintenance dollar on the AC, and it is the difference between a $250 spring visit and a $500 August emergency with a wet mattress.

When to call

Now if there is water on the bed; turn the unit off first. Before June if the unit has never had its pan cleaned. And if you already paid someone to reseal the roof for a leak under the AC and it is still dripping, call us, because the roof was probably never the problem.

Tell us the make of the unit, when it drips, and where the rig sits. We work on site across Sebring, Avon Park, Lake Placid, and the rest of the county.

Frequently Asked Questions

Why is water dripping from my RV AC ceiling unit?

The rooftop unit pulls moisture out of the air and collects it in a pan under the evaporator, which drains out onto the roof through small ports. In Highlands County humidity the pan fills with algae, the ports clog, and the pan overflows through the ceiling assembly. It is the most common AC call we take in July and August.

How much does it cost to fix?

A condensate pan and drain cleaning is $200 to $400 on top of the trip fee. If the AC gasket has compressed and is letting rain in, that is a $200 to $450 gasket replacement. A roof reseal, which is what people brace for, is $500 to $1,200, and it is usually not what this is.

Can I clean the pan myself?

If you can safely get on the roof, yes: pull the shroud, clear the pan and both drain ports, and flush them. Most of our customers should not be on a ladder over a roof, and a tech can do it in the same visit as a coil clean, which the unit almost certainly needs too.

How do I tell a clogged pan from a real roof leak?

Timing. A pan drips after the AC has run for hours on a humid day, rain or no rain. A roof leak drips during or after rain, AC or no AC. If it is dripping on a dry afternoon with the unit running, it is the pan.