So you turn on your split AC, the fan is humming along, but the room stays warm.
Super annoying, right? You expect cool air and instead it just feels like the fan mode.
The good news is this is a common problem, and in most cases, the cause isn’t too complicated. Once you know what’s going on, you can figure out if it’s a quick fix you can handle yourself or if it’s time to call in a pro.
In this post, we’ll break down why your split AC is not cooling but fan is running.
#1. Thermostat Or Settings Issue
This sounds too simple, but it’s often the culprit.
A lot of people accidentally set their AC to “fan” instead of “cool.” When that happens, the blower runs but the compressor doesn’t kick in, which means no actual cooling. Sometimes the thermostat is set higher than the room temperature too.
That makes the system think it doesn’t need to cool, so it just keeps circulating air.
So always double-check your remote or thermostat first. Make sure the mode is on “cool” and the temperature is a few degrees lower than the current room temperature.
If you recently had a power outage, the settings might have reset on their own. Adjust them back and see if the air starts cooling.
Also Read: Can A Thermostat Go Bad?
#2. Dirty Air Filters
Air filters are the lungs of your AC.
If they’re dirty or clogged, the system has to work harder, and cooling performance takes a hit. Over time, the dust build-up can block airflow so much that the indoor coil doesn’t get enough air passing over it.
That leads to weak or no cooling.
The fix is super easy. Just take out the filter, wash it if it’s reusable, or replace it if it’s the disposable kind. A clean filter can make a massive difference in cooling.
Plus, it helps your AC run more efficiently and keeps the air in your room fresher.
Ideally, filters should be cleaned once a month during heavy use.
#3. Dirty Or Blocked Condenser Coils
Your split AC has two main parts – the indoor unit and the outdoor condenser.
That outdoor condenser has coils that are designed to release heat. If they get covered in dust, dirt, or even leaves, the heat can’t escape.
The fan may still be spinning, but without proper heat exchange, the AC won’t cool the air inside.
Take a look at your outdoor unit. If it’s clogged with dirt or surrounded by stuff like plants or furniture, clear it out. Also spray the coils gently with water to wash off dust.
Just be careful not to bend the fins!
Keeping that outdoor unit clean and well-ventilated is one of the easiest ways to prevent split AC not cooling but fan is running issue.
Also Read: Why Is My A/C Running but Not Cooling the House?
#4. Low Refrigerant
Refrigerant is the lifeblood of your split AC. If there’s a leak or the refrigerant charge is low, the compressor can run, but it won’t produce enough cooling.
Low refrigerant usually means there’s a leak somewhere in the system.
These leaks can develop in the copper tubing, joints, or coils, often from wear and tear, corrosion, or even poor installation.
Another sign of low refrigerant is ice buildup on the indoor coil. As the gas level drops, the pressure in the system falls, and the coil gets too cold, causing it to freeze over.
You might even notice weak airflow, warm air, or ice forming on the coils.
This isn’t a DIY fix. Adding refrigerant requires a licensed technician, and the leak needs to be found and sealed first. If you just top it off without fixing the leak, the problem will come back.
If your AC used to cool fine but now struggles, low refrigerant could be the reason.
#5. Compressor Problem
The compressor is basically the heart of your split AC. It pumps refrigerant through the system, and without it, cooling just doesn’t happen.
Sometimes the compressor doesn’t start even though the fan is running.
That can be caused by a faulty capacitor, an overload protector, or the compressor itself failing.
If the fan is blowing but you don’t hear the usual hum of the compressor kicking in, this might be the issue. Unfortunately, compressor repairs are not DIY friendly. They require testing with electrical tools and professional handling.
A technician can tell if it’s just a capacitor or if the whole compressor needs replacement.
Also Read: Why Is My AC Squealing?
#6. Frozen Evaporator Coil
A frozen indoor coil can also cause the fan to run without cooling.
When ice builds up on the coil, it blocks airflow, and the system ends up blowing air that feels warm or weak. Several things can cause this:
- Dirty filters
- Restricted airflow
- Low refrigerant
If you notice ice on the coil or even water dripping when it melts, turn off the AC right away.
Let the coil thaw completely before restarting. Then look for the root cause. Start with cleaning the filter and checking airflow.
If the coil keeps freezing, you may need a professional to inspect for refrigerant issues.
#7. Electrical Or Capacitor Fault
Electrical and capacitor issues can also be the reason behind Split AC not cooling but fan is running.
Your AC relies on capacitors to start both the fan motor and the compressor. If the capacitor for the compressor fails, the fan will still spin but the cooling cycle won’t start.
Electrical faults like burned wiring or tripped breakers can also cause similar problems.
A bad capacitor is one of the most common issues technicians deal with.
It’s a small, inexpensive part, but it can stop your AC from cooling completely. Since it involves electrical work, it’s better to let a pro handle it for safety reasons.
What To Do If Split AC Not Cooling But Fan Is Running
If your split AC is blowing air but not cooling, don’t panic. Here’s a simple checklist you can run through before calling a HVAC technician:
- Check thermostat settings and make sure it’s set to “cool.”
- Clean or replace the air filter.
- Inspect the outdoor unit and clean any dirt or debris blocking the coils.
If none of those quick fixes solve the problem, it’s probably time to bring in a professional.
Issues like refrigerant leaks, compressor failures, or capacitor problems need special tools and expertise. Don’t keep running the unit while it’s not cooling, because that can cause further damage.
Bottom Line
A split AC that runs its fan but doesn’t cool can be caused by simple things like wrong settings or dirty filters, or more serious problems like refrigerant leaks or a bad compressor.
Always start with the easy checks: thermostat, filters, and outdoor unit.
If that doesn’t do the trick, call an HVAC technician to dig deeper.
Taking care of your AC with regular cleaning and maintenance goes a long way toward avoiding these problems. The sooner you spot and fix small issues, the less chance you’ll be stuck sweating on a hot day.