Air conditioner leaks: How to spot & fix the problem

When you have air conditioning installed in your home, knowing how to properly look after it is just as important as choosing the right system. Failing to maintain your air conditioning unit can limit its effectiveness, reduce its lifespan, and potentially cost you lots of money in repairs. 

One of the most common problems with poorly serviced air conditioners is leaking. If you encounter a leak, you should investigate it straight away as minor leaks may indicate that your air conditioning unit has a more severe problem. 

We've put together this guide to ensure you can identify a leak and take steps to reduce the risk of leaking. Here, we explain how to perform a basic check and find any problems in your air conditioning system.

Signs that you may have an air conditioning leak

You should look for several signs to determine if a leak is causing a problem with your air conditioning system. As with any system problem, you must seek the advice of a heating, ventilation and air conditioning (HVAC) technician to prevent injury to yourself or damage to your air conditioning unit. 

Here are four signs that your air conditioning unit may not be operating as it should.

1. Your system isn’t blowing cold air 

If hot air is coming out of your vents when the temperature is set to cool, then this can be a big sign of an air conditioner leak. This could be one of the first checks you make to pinpoint the problem. Hold up a hand to the vent to test the temperature. If it’s warm, you’ll know something isn’t right.

2. Your air conditioning system isn’t cooling as it should 

Refrigerant, the liquid solution used in cooling systems such as your air conditioning unit, is a crucial part of the cooling process. It absorbs the heat from your home and releases it into the air outside. If the refrigerant levels are low, this may be due to a leak, and it’ll take much longer to cool your home as a result.

3. Your indoor unit is noisy 

If you hear a gurgling or rumbling sound coming from your system, this can be a sign that several things are wrong, like cracks or breakages in refrigerant coils, or a leak. To determine what the problem is, you must contact a trained professional to inspect your air conditioning unit.

4. Your electricity bills are unusually high

Pay close attention to the amount you’re spending on your electricity bills. If you’re finding them much higher than usual, or you have to rely on alternative heating and cooling systems alongside your air conditioning units, this is a telltale sign that things aren’t working as they should. 

If your thermostat settings are correct and your usage patterns haven’t changed significantly, there could be an underlying issue with your home’s air conditioning.

How to find out if your air conditioner is leaking

If you suspect that your air conditioning system is leaking, the next step is to confirm it. Luckily, there are several ways to troubleshoot the problem and get your system back up and running as it should.

1. Air conditioning leak detector

Some older air conditioning units* use Freon as a form of refrigerant. Leaks caused by Freon are not always obvious to spot, so you may need to use alternative methods to identify a leak.

*Mainly, this will be any air conditioning units installed before 2010, when manufacturers began phasing out the use of Freon. If you are unsure about the refrigerant your system uses, contact a qualified HVAC engineer for support.

Method 1 - Add a fluorescent dye to the system

By adding a fluorescent dye to your refrigeration system, you’ll easily be able to identify the exact point of the leak. If there is a leak, the dye will change colour in the precise location of it. This method will require UV lighting and professional advice.

It’s important that you don’t attempt to do this job yourself. Only a trained HVAC technician can add dye to an air conditioner system.

Method 2 - Try the bubble method

An old trick to spot a leak is to apply a soapy solution to an area you suspect there is a leak. Escaping refrigerant will produce bubbles where the leak is. One problem with this method is that if a leak is very small, you may not see any bubbles, meaning you may well miss the leak entirely.

2. Ask a HVAC technician to conduct an air conditioning leak test

Another way of helping yourself to get to the root of the problem is by purchasing a leak test kit designed specifically for air conditioning systems. It’s best to get a qualified HVAC technician to carry out this work for you, as there are several different types of testing kits, and it’s essential to use the correct one (in the right way) for your system.

Air conditioning leak detectors work by identifying the amount of refrigerant in your system. If there is too little, it could indicate a leak. 

If you aren’t sure about any of the methods mentioned, you must seek help from an HVAC technician.

How to repair air conditioning leaks

Remember, this is not a DIY job. Only qualified technicians with the skills and knowledge needed to repair air conditioning units should attempt to fix any issues identified.

So you know what to expect if and when you need to contact an engineer, here’s an overview of what they’ll likely do to get your air conditioning system back up and running.

1. Inspect the drain tray, compressor and filter

First, your engineer will remove the window unit and outer cover to inspect whether there is a build-up of debris in the drain tray - emptying this and keeping the system clean can mitigate the risk of problems occurring. The engineer will then check the system’s air compressor and filter to see if there is any sign of a leak.

2. Apply leak sealant to affected areas

After identifying the site of the leak, they will apply an air conditioning leak sealer to the affected area. This waterproof sealant will repair any hole or crack in the system’s rubber hoses, gaskets or o-rings.

3. Reassemble and recheck the system

Finally, the engineer will put the air conditioning system back together and restart your unit to confirm that the leak has been repaired. If there are still signs of leaking from anywhere within the system, the engineer will carry out repeat checks and add more sealant if necessary.

More information and guidance

Head to our dedicated air conditioning blog page for more information and expert guidance on keeping your home’s air conditioning system fit and healthy.

Or, for support with urgent issues about your air conditioner, we have trained professionals ready to chat. You can use our live chat feature to ask our air conditioning experts questions or request tailored advice on how to spot and fix air conditioning leaks.