RV air conditioner not cooling: what is wrong and what the repair costs

An RV air conditioner that runs but does not cool is, from May to October, the most urgent call we take. It is also one where the price range is enormous: $200 to $600 for the common repairs against $1,200 to $2,500 for a replacement unit. Getting the diagnosis right is worth real money, and a surprising share of “dead” rooftop units come back to life for the price of a capacitor or a coil cleaning.

Check this first (fifteen minutes)

1. Measure the split. Put a thermometer at the return air grille and another at a supply register. A healthy unit gives you roughly a 16 to 22 degree drop. If you have that split on a 92-degree day, the AC is working and the problem is heat load and humidity, not the unit.
2. Check the power source. On a 30-amp pedestal with a converter, a water heater on electric, and a residential fridge running, an AC can be starved. Low voltage at the pedestal, common at the fish camps and in older parks on a hot afternoon when everyone on the loop is running AC, makes compressors struggle and start capacitors fail.
3. Look at the filters and the return. RV AC filters are small, they clog fast with oak pollen in spring and mildew all summer, and a clogged filter freezes an evaporator. Pull them and look.
4. Look for ice. Ice on the evaporator coil inside the ceiling assembly means airflow or a thermostat problem, not a refrigerant problem. Shut it off, run the fan only until it thaws, and see whether it cools normally afterward.
5. Check the pan. If the unit is also dripping inside, the condensate pan is clogged and the unit is sitting in its own water, which does nothing good for the evaporator. See AC dripping water inside.
6. Go up top if you safely can and look at the condenser coil. Ours fill with pollen, leaf litter, and mildew. A packed condenser cannot reject heat, and in this humidity that is the difference between cooling and not.

What is usually wrong

These match the pricing page on top of the $75 to $150 trip fee and $125 to $190 hourly labor.

The Florida reality about RV air conditioning

A rooftop RV air conditioner is a small appliance asked to do something enormous. A 15,000 BTU unit in a thin-walled box with single-pane windows, parked in full sun at 92 degrees and 79 percent humidity, is working as a dehumidifier as much as a cooler, and every gallon of water it pulls out of the air is capacity it did not spend on temperature. That is not a defect and no repair changes it.

What the honest version of that conversation includes:

• Judge by split, not by setpoint. A unit making a 20-degree drop is doing its job. If the coach is still 80 degrees, the unit is not the problem.
• Humidity is the load. A coach that feels sticky at 78 is a coach whose unit is short-cycling on temperature before it has removed enough water. Running the fan on low instead of auto, and running the unit longer at a slightly higher setpoint, often feels cooler than a lower setpoint.
• Shade is worth more than BTUs. A rig under trees, like the wooded sites at Peace River in Wauchula, is a different thermal problem from the same rig on an open lakefront site.
• Two units beat one big one. Larger rigs have a front and rear unit for a reason.
• Pedestal voltage matters. A 30-amp fish-camp pedestal sagging on a hot afternoon is hard on a compressor and it is a real cause of premature failures.

Why so many ACs die in July here

Three mechanisms. Pollen and mildew choke the condenser slowly over a couple of seasons until the unit can no longer reject heat, at which point the compressor runs hot and does not last. The start capacitor, an electrolytic component, degrades faster with hours run, and a Highlands County unit runs from late April into November. And lightning: Florida records more lightning per square mile than any other state, and a strike near a park’s electrical service puts a surge through every pedestal that kills control boards outright. A coil clean in the spring and a surge protector on the pedestal are the two best maintenance dollars on these units in this county.

If you are living in the rig

Say so when you call. A full-timer or a summer resident with no cooling is a different priority from a stored rig, and we schedule it that way. If the unit cannot be repaired the same day, we will tell you honestly what the lead time on a replacement unit looks like rather than leaving you guessing in the heat.

What to expect on the call

Tell us the make and BTU rating if you can read it off the shroud or the interior assembly, what the split is, whether the compressor is starting, and what the pedestal is giving you. We work on site across Sebring, Avon Park, Lake Placid, Lorida, and Okeechobee, and the Dometic and Coleman AC page covers what fails first on each.