October 2, 2026 · 3 min read
Why "just recharge it" is usually not the answer
Most rooftop RV air conditioners are sealed systems, much like a household fridge. They leave the factory holding a set amount of refrigerant, and they have no service ports for topping it up. If the unit is low on refrigerant, there is a leak somewhere, and adding more without finding that leak only buys a little time.
Fixing a real refrigerant leak means finding it, repairing it, fitting access ports and recharging to the correct amount. Handling refrigerant is regulated, and on an older unit that work can cost close to what a replacement would. That is why a proper diagnosis should come before anyone talks about a recharge.
The good news is that lost refrigerant is not the most common reason an RV air conditioner struggles. Airflow and power problems happen far more often, and you can check many of them yourself.
Simple checks you can do at the campsite
Start with the return air filters in the ceiling assembly. Dust from gravel roads and cottonwood fluff clog them quickly, and a blocked filter starves the unit of air. Wash or replace them, and let them dry fully before you put them back.
Next, look for ice. The cooling coil behind the filter can freeze over. Another sign is airflow that gets weaker the longer the unit runs. If you see either one, switch to fan only until the ice melts, clean the filter and try again. If it keeps freezing, there is an airflow or refrigerant problem that needs a technician.
Then check your power. RV air conditioners do not handle low voltage well, and low voltage is common at busy campgrounds on hot afternoons when every site is running its AC. If the compressor keeps shutting off, or you hear it try to start and then quit, the cause may be low voltage or a weak start capacitor. On a 30 amp hookup, avoid running the microwave, an electric water heater and the AC at the same time.
Help your AC keep up in prairie heat
Even a healthy rooftop unit can only cool the inside air by so much compared with the air outside. On a blazing afternoon with sun on the roof, it may run nonstop and the coach can still feel warm. That alone does not mean the unit is broken.
When you can, park so your largest windows face away from the afternoon sun. Put out the awning, close the blinds and use reflective window covers. Start cooling in the morning, before the coach heats up, instead of waiting until the afternoon. Also make sure the condenser coil under the rooftop shroud is not packed with debris or covered in flattened fins.
Check the ceiling vents and ducting too. A closed vent or a crushed or loose duct can leave one end of the coach much warmer than the other, even when the unit itself is working fine.
When to bring it to Horton RV in Calgary
Book a visit if the compressor will not start, the unit hums or clicks without cooling, it keeps tripping the breaker, the coil still freezes after you clean the filter, or you see oily residue around the tubing inside the rooftop unit. These signs point to failed electrical parts, worn motors or a leak, and all of them need proper testing.
Our Calgary team can diagnose the unit, replace failed parts such as capacitors, fan motors or thermostats, and tell you honestly whether repair or replacement makes more sense for your rig. If hail cracked the shroud or damaged the coil fins, we can also inspect and document the damage for an insurance claim.
Having it checked before summer trips beats finding out on the hottest weekend of the year, far from a repair shop.
Common questions
Can I recharge my RV air conditioner myself?
In most cases, no. Rooftop RV units are usually sealed and have no service ports. Low refrigerant means there is a leak that has to be found and repaired first, and handling refrigerant is regulated. A technician should diagnose the unit before any recharge is considered.
Why does my RV air conditioner keep freezing up?
The usual cause is poor airflow, such as a dirty filter, blocked return vents or a weak fan. Running the AC on a cool, humid night can also cause icing. If it keeps freezing after you clean the filter, low refrigerant or a failing part may be to blame, and it should be checked.
Is it worth repairing an older RV air conditioner?
It depends on what failed. Electrical parts like capacitors, thermostats and fan motors are often worth replacing. A refrigerant leak on an older sealed unit often makes replacement the better value. We will explain what we find so you can decide.