There’s nothing worse than your air conditioner failing on a sweltering summer day or a frigid winter night. Your home’s climate control system is more than a luxury; it’s essential for your comfort, health, and well-being. When it suddenly stops working, it can feel like a major crisis.

But don’t panic. While many issues require a professional, some common AC emergencies can be resolved with a few simple checks. This guide will help you diagnose the five most frequent AC problems and tell you what steps to take before making the call.

1. The AC Refuses to Turn On

You’ve set the thermostat, but nothing happens. The unit is silent, and no air is flowing. This is the most common AC issue, and thankfully, the solution is often simple.

What to Check Before You Call:

  • Check the Thermostat: Is it set to “Cool” (or “Heat” in winter) and a temperature that should trigger the system? Are the batteries fresh? Sometimes the simplest oversight is the culprit.
  • Check the Power: Your AC has two main power sources. Check the circuit breaker for the indoor unit in your main electrical panel. Then, check the external disconnect switch (usually in a small box near the outdoor unit) to ensure it is in the “On” position.
  • Check the Air Filter: A severely clogged air filter can restrict airflow so much that it causes the system to overheat and shut down automatically as a safety measure.

2. The AC is Running, But Blowing Warm Air

If your system is humming away but the air coming from the vents isn’t cold, your comfort and electricity bill will both suffer. This indicates the cooling function isn’t working correctly.

What to Check Before You Call:

  • Confirm Thermostat Settings: Double-check that the thermostat is set to “Cool” and not just “Fan,” which only circulates air without cooling it.
  • Clean the Outdoor Unit: The large outdoor condenser unit needs to breathe. If it’s covered in dirt, leaves, or grass clippings, it can’t release heat effectively. After turning the power off at the external disconnect switch, you can gently hose down the unit’s fins to clear debris.
  • Check the Air Filter: Once again, a blocked filter can be the villain. A dirty filter restricts airflow over the evaporator coils, which can cause them to freeze over and prevent the system from cooling properly.

3. Water is Leaking From the Indoor Unit

Noticing a puddle of water around your indoor AC unit is a clear sign of trouble that should never be ignored. This water can damage walls, ceilings, and floors and lead to mould growth.

What to Check Before You Call:

  • Inspect the Condensate Drain Line: Your AC removes humidity from the air, which collects in a pan and drains away through a pipe (the condensate line). If this line becomes clogged with algae or debris, the water will back up and overflow. You may be able to see the blockage at the end of the drainpipe.
  • Check the Air Filter: A clogged filter can cause the evaporator coils to freeze. When the ice melts, it can overwhelm the drain pan, causing it to leak.
  • Turn the System Off: If you see a significant leak or a frozen coil, it’s best to turn the AC off to prevent further water damage and let the system thaw before a professional arrives.

4. The Unit is Making Grinding, Banging, or Squealing Noises

Your AC should produce a consistent, low hum. Any sudden, loud, or unusual noises are a mechanical cry for help and signal that something is seriously wrong inside the unit.

  • Squealing often points to a problem with the belt or motor bearings.
  • Grinding or Metal-on-Metal could mean the motor’s bearings are completely shot.
  • Banging or Clanking may indicate a loose or broken part, like a piston, connecting rod, or crankshaft.

What to Do Immediately:

  • Turn the system off immediately. Continuing to run the unit with these sounds can lead to a catastrophic failure of a major component, turning a potentially simple repair into a full system replacement. This is not a DIY situation.

5. The Vents are Releasing Foul Odours

Unpleasant smells from your AC system are a clear sign that something needs to be addressed.

  • A Burning Smell: This is the most dangerous. It could be an overheated motor or a wiring issue. Turn the system off at the breaker immediately and call for emergency service.
  • A Musty or “Dirty Sock” Smell: This typically indicates the growth of mould or mildew on the system’s evaporator coil or in the ductwork due to excess moisture.

What to Do Immediately:

  • For a burning smell, turn the power off now.
  • For musty smells, a professional cleaning is required to safely remove the mould and prevent it from spreading throughout your home. A new air filter is a good first step, but it won’t solve the underlying problem.

Don’t Sweat It, We’ve Got You Covered

While these checks can help you solve minor issues, an air conditioning system is a complex piece of machinery. When you’re faced with strange noises, leaks, or a system that just won’t work, our team is here to restore your comfort and peace of mind.

For 24/7 Emergency Air Conditioning Service in Sydney & Melbourne:

When you need fast and reliable relief, make the right call.

📞 1300 229 897