Why Is My Split System Not Blowing Cold Air?
Perth summers are no joke. When your split system stops blowing cold air right when you need it most, it’s more than just an inconvenience, it can make your home or business genuinely uncomfortable.
The good news is that a split system not blowing cold air is one of the most common air conditioning problems, and in many cases, the cause is straightforward. This guide walks you through the most likely reasons your split system isn’t cooling and what to do about each one.
If you’ve worked through the basics and your unit still isn’t cooling, our team at Hurricane Air is ready to help. We provide fast, reliable air conditioner repairs across Perth.
Quick Summary
If your split system isn’t blowing cold air, here are the most common causes:
- Wrong mode — Check your remote and make sure it’s set to Cool (❄)
- Dirty filters — Blocked filters restrict airflow and reduce cooling
- Low refrigerant — A gas leak means the system can’t cool properly
- Frozen evaporator coil — Ice buildup stops heat exchange from working
- Blocked outdoor unit — Debris around the condenser prevents heat from escaping
- Faulty compressor — The system runs but can’t drive the cooling cycle
- Undersized system — The unit may be too small for your space
1. The Unit Is Set to the Wrong Mode
Before assuming something is broken, check your remote control settings. Many split systems have multiple modes — Cool, Heat, Fan, Dry and Auto. If the unit has been accidentally switched to Fan or Dry mode, it will circulate air without actually cooling it.
What to do:
- Press the Mode button on your remote until the snowflake symbol (❄) or ‘Cool’ appears on the display.
- Set the temperature below your current room temperature — ideally between 22°C and 24°C.
- Give the system a few minutes to start producing cold air.
This is the quickest fix to check and takes less than a minute.
2. Dirty or Blocked Air Filters
Clogged filters are one of the leading causes of poor cooling in split systems. When the filters are blocked with dust, pet hair or debris, airflow is restricted and the unit struggles to pull warm air in and push cold air out. Over time, blocked filters can also cause the evaporator coil to freeze over, which further reduces cooling performance.
What to do:
- Turn the unit off and remove the front panel to access the filters.
- Rinse filters gently under lukewarm water and allow them to dry completely before reinserting.
- Aim to clean your filters every four to six weeks during heavy use periods.
Regular filter cleaning is one of the simplest ways to keep your split system running efficiently. If you’d prefer a professional clean, our team offers scheduled air conditioner maintenance in Perth to keep your system performing at its best.
3. Low Refrigerant (Gas) Levels
Refrigerant is the substance that absorbs heat from inside your home and releases it outside. If your system is low on refrigerant — either due to a slow leak or improper installation — it simply won’t be able to cool your space effectively.
Signs of low refrigerant include:
- The unit runs constantly but never reaches the set temperature
- You hear a hissing or bubbling sound near the indoor unit
- Ice forms on the refrigerant lines or indoor coil
- Your energy bills have increased noticeably
Refrigerant issues must be handled by a licensed technician. In Australia, it’s illegal for unlicensed individuals to handle refrigerants. Our air conditioning repair team can locate the leak, carry out the repair and regas the system to the correct level.
4. Frozen Evaporator Coil
The evaporator coil inside your indoor unit can sometimes freeze up, which sounds counterintuitive but actually stops the system from cooling properly. When ice forms on the coil, it creates an insulating barrier that prevents heat exchange from occurring.
A frozen coil is often caused by:
- Dirty or blocked air filters (insufficient airflow)
- Low refrigerant levels
- Running the system at very low temperatures for extended periods
What to do:
- Turn the unit off and switch it to Fan mode to allow the ice to melt naturally.
- Clean the filters and check for any obvious blockages.
- If the coil freezes again after restarting, call a technician, there’s likely an underlying issue causing it.
5. Dirty or Blocked Condenser (Outdoor Unit)
The outdoor unit (condenser) is responsible for releasing the heat absorbed from inside your home. If it’s covered in dirt, leaves, grass or debris, it can’t expel heat efficiently — and your split system will struggle to cool. Perth’s dusty conditions and windy weather make this a common problem, especially if the outdoor unit is near garden beds or exposed areas.
What to do:
- Turn the system off and clear any obvious debris from around the unit.
- Gently rinse the exterior fins with a garden hose. Never use a pressure washer as this can damage the fins.
- Ensure there is at least 50cm of clearance around the unit for adequate airflow.
- For a thorough internal clean, book a professional service.
6. The Compressor Is Faulty
The compressor is the heart of your air conditioning system. It pressurises the refrigerant and drives the entire cooling cycle. If the compressor is failing or has stopped working entirely, your split system will blow air — but it won’t be cold.
Compressor issues are more likely in older systems or units that haven’t been regularly serviced. Signs include:
- The outdoor unit is running but making loud or unusual noises
- The system starts then immediately shuts off
- No change in room temperature despite the system running for a long time
Compressor repairs and replacements require a licensed HVAC technician. Depending on the age and condition of your system, it may be more cost-effective to replace the unit entirely. Our team can advise you honestly on whether a repair or a new installation is the better option for your situation.
7. The System Is Undersized for the Space
If your split system has never cooled your space effectively — not just recently — it may simply be too small for the room or home it’s installed in. An undersized unit will run constantly, struggle to reach your set temperature and wear out faster than it should. This is a particularly common issue in Perth, where summer temperatures regularly exceed 35–40°C and place significant demand on air conditioning systems.
If your current system is too small, our team can recommend the right size unit and provide a quote for supply and installation.
When to Call a Professional
Some cooling issues can be resolved with a quick check and clean. But if you’ve worked through the steps above and your split system still isn’t blowing cold air, it’s time to get a licensed technician involved.
You should call a professional if:
- The unit is blowing warm air regardless of settings
- You suspect a refrigerant leak
- The system is making unusual noises or producing bad odours
- Ice is forming on the indoor or outdoor unit
- The system keeps shutting itself off
- Your energy bills have increased without explanation
Attempting to fix refrigerant, electrical or compressor issues without proper licensing is not only unsafe — it can void your warranty and cause further damage.
Prevent Problems with Regular Servicing
Most of the issues covered in this guide can be prevented with regular professional servicing. Annual maintenance helps catch small problems early, keeps your system running efficiently and extends its lifespan.
Our air conditioner maintenance service includes filter cleaning, coil inspection, refrigerant checks, electrical testing and a full performance assessment — everything needed to keep your split system cooling reliably through Perth’s toughest summers.
Need Help With Your Split System in Perth?
If your split system isn’t blowing cold air and you’re not sure why, Hurricane Air is here to help. We’re a Perth-based family business with over 15 years of experience repairing all major brands of split systems — Daikin, Mitsubishi Electric, Toshiba, Panasonic and more.
We provide honest advice, upfront pricing and fast response times across Perth.
Get in touch with our team today to book a repair or request a quote.
