Keep Your RV AC Running All Summer

Your RV's AC unit runs harder in Florida than almost anywhere else in the country. Between May and October, it's not uncommon for a rooftop unit to cycle for 14 hours straight on a 95-degree day. That kind of demand shortens component life significantly. After 11 years and hundreds of AC repairs across Martin County, here's what I've learned about keeping your system running all summer.

Clean or Replace Your Filter Monthly

This is the single most impactful thing you can do. A dirty filter restricts airflow across the evaporator coil, forcing the compressor to work harder and reducing cooling output by up to 25%. In Florida, where pollen, dust, and humidity are constant, filters clog faster than in drier climates. Pull the filter from inside the ceiling shroud, wash it with warm water and mild soap, let it dry completely, and reinstall. If it's damaged or thinning, replace it. Dometic and Coleman filters are available at most RV supply stores for under $15.

Get Your Capacitor Checked

The run capacitor is the #1 failure point in RV AC units, and we replace more capacitors than any other component between June and September. A capacitor stores the electrical charge that starts and runs the compressor motor. Florida's heat causes capacitors to swell and fail prematurely. Symptoms of a failing capacitor include the AC humming but not starting, the compressor cycling on and off rapidly, or the unit blowing warm air intermittently. A new capacitor costs $15 to $30, but the labor to diagnose and replace it runs $120 to $200 total. Compare that to the $1,500+ you'd spend if a failed capacitor burns out your compressor motor.

Clean the Coils Twice a Year

Your AC has two sets of coils: the evaporator (inside, behind the filter) and the condenser (outside, on the roof). Both collect dirt, pollen, and grime that reduce heat transfer efficiency. Per Dometic's maintenance guidelines, coils should be cleaned every 6 months in high-use environments. For the condenser coils on the roof, turn off the AC, remove the shroud, and gently spray the coils with a garden hose (never a pressure washer). For the evaporator, use a foaming coil cleaner from an HVAC supply store and let it drip into the drain pan.

Ensure Proper Airflow Around the Rooftop Unit

Your rooftop AC unit needs clear airflow around the condenser to dissipate heat. If branches, awning fabric, or other obstructions block airflow, the condenser can't reject heat efficiently, and the compressor overheats. Make sure there's at least 12 inches of clear space on all sides of the rooftop unit. Also check that the roof gasket is intact. A deteriorating gasket lets hot outside air mix with cold conditioned air, reducing efficiency.

Know Your Electrical Limits

A 13,500 BTU rooftop AC draws about 12 to 13 amps on a 120V circuit. If you're on a 30-amp hookup, that's nearly half your available power just for one AC unit. Running a microwave, water heater, and AC simultaneously on 30 amps will trip the breaker every time. If you have two AC units, you need a 50-amp hookup or a soft-start kit on at least one unit. Soft-start devices reduce the startup surge from 30+ amps down to about 18, which can make the difference between a tripped breaker and a cool rig.

When to Call a Professional

If your AC is blowing warm air and the filter is clean, it's time to call. The issue is likely electrical (capacitor, fan motor, compressor) or refrigerant-related, and both require tools and expertise to diagnose safely. Don't try to recharge refrigerant yourself. RV AC systems are sealed units, and improper charging can damage the compressor permanently. Call 772-758-0499 and describe the symptoms. We can usually narrow down the likely cause over the phone and come prepared with the right parts.