Air Conditioner Not Cooling? 5 Easy Ways To Fix [Guide]

When your air conditioner is not cooling properly, it can be hard to detect. At first, it might seem to take a bit longer to cool your home. Next, you might hear a few strange sounds, and sniff a few noxious smells. Then, before you know it, you’re waking up in a pool of sweat because your air conditioner has stopped cooling altogether—a scenario you want to avoid!

So if you’re starting to see the subtle signs, it’s important to take action early and get to the root cause of your air conditioning problem. Thankfully, a lot of causes for air conditioner malfunctions are easy to address. With a few simple precautions, and some regular maintenance, you can keep your air conditioner running optimally all summer long.

But before you get to that, let’s focus on the matter at hand: here’s where to start when your air conditioner is not cooling.

1. Check the thermostat

The key to troubleshooting is to start simple, and in this case that means turning your air conditioner off and on again. If it isn’t blowing cool air, you should check the setting to ensure that it has been correctly configured at the thermostat. This is an especially big issue with ducted air conditioners that use zones, as there’s often multiple zones and thermostats.

Zoning technology cuts off cooling to rooms that aren’t in use, and if you have that setting manually configured, you could easily find yourself in a warm room while your AC continues to cool the rest of your home. All you need to do is restore cooling to your chosen room through the app or thermostat.

Other things to look for are temperature settings, cycle options, and air con timers – all of those features are great, but they can easily catch you off guard.

2. Double check the doors

If your air conditioner settings are exactly as you like them, the next thing to check are your doors and windows. Even a single open door can drastically affect your air conditioner’s performance, and easily make it feel as though it simply isn’t cooling. The same applies for windows, which can easily evade our attention, and leave us wondering where the cool air is going.

In older homes, doors can also be quite draughty, with plenty of space beneath and above for warm air to enter your home and circulate. Homes are often negatively pressurized, too, which can cause warm air to be sucked through even the smallest gaps. Easy solutions include things like door snakes, which can create a good seal and keep cool air circulating inside.

3. The compressor conundrum

In a lot of ways, the compressor is the heart of your air conditioner—whether split system or ducted. It controls the air pressure within the system, which allows the thermodynamic transfer to occur seamlessly and create the beautiful cool air we crave. So, if your compressor goes, then you’re sure to notice a fast downturn in the cool air produced by your air conditioner.

Luckily, this issue is one of the less subtle ones. You might have noticed that your air con sounds like it’s working harder than ever, but it’s still not keeping you cool. If so, you probably have compressor issues. Compressors often get noisier and noisier as they near the end of their lives, and that’s especially true in older models. It can be quite disruptive, but it’s a terrific alarm and a good reminder that your air con is due for a service.

4. Blockages

Another source of air conditioner complication is blockage, and it can occur in various parts of the system. Blockages usually start in the filter, which is easy to clean. However, if it’s not cleaned frequently then the filter can become overwhelmed, and dust or debris can make their way through your system. In ducted air conditioners that can be especially problematic, because there are large and inaccessible lengths of ducting capable of hiding serious blockages. It’s tricky to tell if your air conditioner is not cooling because of a blockage, but smell is one thing that can give it away. If your air conditioner has a musty or mouldy smell, then there may be a blockage affecting its performance.

5. If none of that works, you may just need a bigger system

Finally, there’s a one size fits all solution to air conditioners that don’t cool properly: replace them! Air conditioners can last a long time, but like all appliances, they have a shelf life. They also have optimal performance ratios. If your air con consistently fails to cool your home properly, then it could be a sign that it’s just too small for the area it’s in. It might also be on its last legs. If that’s so, you should turn your mind to installing a ducted or split system replacement with the power to service a larger space.