How to get the most out of your air conditioning

With temperatures heating up, we delve into how you can maximise the performance of your car's a/c.

By Shell on Dec. 14, 2023

Most of us probably don't think too much about how we use our car's air-conditioning (a/c) system. Which is entirely understandable. Jumping into a car that's been sitting in the Australian summer sun means we want relief – fast. But short of getting lucky, grabbing randomly at your a/c switches isn't the best way to maximise its performance. If you want to cool your car fast and keep it comfortable, here are the steps to follow.

Which HVAC?

First, you need to know what kind of heating, ventilation, and air-conditioning (HVAC) system your car has – manual or automatic – because that will dictate your button-pressing strategy.

Identifying an automatic, electronically controlled HVAC system – often called 'climate control' – is easy. If you have a digital readout showing temperature, fan speed, air distribution, air recirculation and other HVAC aspects such as demisters, you've got an auto system. If you only have a bunch of rotary dials or buttons controlling key HVAC elements, you've got a manual system.

Manual HVAC

The good news is even the most basic HVAC system has everything needed to cool a car and keep it comfortable. Ultimately, it's all about getting the HVAC system to pump as much chilled air into the cabin as it can while doing your bit to help the hot air be expelled efficiently.

To do this:

Adjust the temperature to its lowest setting.
Adjust the fan speed to its maximum.
Activate the cabin recirculation to stop the hot outside air being drawn in.
Activate the a/c. If your system has a 'max a/c' or similar setting, choose that.
To maximise the cooling effect, set your air distribution to windscreen/foot-level and drop your windows as you drive off – this will help to push trapped hot air out of the cabin.
Once you've been moving a few seconds, close your windows, switch the air distribution to face level and let the a/c do its work.
When the desired temperature has been achieved, adjust fan speed, temperature and distribution as desired to maintain comfort.

Automatic HVAC

Some auto HVAC systems can be a bit overwhelming at first glance but as the name suggests, they're designed to do all of the hard work for you. It's really very simple. Just look for the 'auto' button and press it, then crank the temp dial to its lowest setting. Your job, aside from initially dropping the windows as you drive off to help expel hot air, is now done – the HVAC system will automatically engage air recirculation and whatever fan-speed and air-distribution settings are needed to cool the cabin to your desired temperature as quickly as possible.

Auto setting isn't doing it for you? Simply pressing the 'auto' button to disengage it or altering a fan-speed, air-distribution or other key settings will give you full manual HVAC control, allowing you to adjust everything as you would on a manual system.

Is your a/c healthy?

Air-conditioning systems can leak, allowing their refrigerant gas to escape, or suffer from compressor problems, blocked cabin filters and other issues that affect their performance. Refrigerant gas is also a consumable, so even a system in perfect condition will lose gas and effectiveness as time passes – sometimes as much as 10 per cent annually. If you've followed these steps and your a/c still isn't blowing cold, it might need a regas or service by a mechanic or a/c specialist to regain its full cooling capability.

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