• Park in the shade
• Start gently
• Use it regularly
• Shut it down before stopping
First of all you need to know what kind of air conditioning your vehicle has – regulated manually or fully automatic – because to some extent, how you use it depends on the type of aircon fitted. However, there are still some overriding best practice principles that will help you get the best out of whichever you have, as they both have the same goal. So, what’s the difference?
Put simply, with manual aircon, the driver sets the temperature, air flow direction and the speed of the blower, adjusting these three to maintain the correct balance, whereas with automated ‘climate control’ as it’s generally called, all the driver needs to do is set the desired temperature and the system does the rest, automatically compensating for changes on the outside to ensure the temperature inside remains constant.
To help the performance of your aircon, there are some practical steps that you can take, such as parking in the shade or, if practical, with the windows open slightly, so that it doesn’t get so hot inside and the system doesn’t have to work so hard to reach your ideal temperature.
Irrespective, don’t be tempted to start the car, whack up the system to maximum and leave the car with the engine running for a few minutes to cool the car, because the aircon actually works much more efficiently when the engine is at its normal operating temperature and the vehicle is being driven.
Instead, it’s best to open all the windows to let the hot air escape and once you’ve set off, switch on the aircon and close the front windows, which will force more hot air from the car, before then closing the rears and letting the system take over.
Similarly, if your vehicle has climate control, you will probably have noticed that once activated, there is a delay, as it starts off quite gently before gradually increasing in speed and reducing the temperature, so try and replicate this example with a manual system.
When it comes to the temperature, set it at a sensible level, such as 20C, rather than forcing the system to try and reach a temperature where you’d normally need to put on your central heating!
If your vehicle is equipped with a start-stop function, which is designed to reduce overall exhaust emissions and reduce fuel consumption by stopping the engine whenever possible, you may find that the performance of the aircon reduces when the engine isn’t running. This is because as the engine stops, so does the compressor in the aircon system, meaning it can’t be kept as cool, and the air coming through the vents soon warms up.
Although some more modern vehicles will restart automatically as the interior temperature increases, most do not. So, to maximise the performance of the aircon when the conditions are particularly hot and you are in heavy traffic, it could be better to override the start-stop function, to let the engine run continuously, which will keep the aircon running consistently and the occupants cooler. In addition, in extreme heat, you can use the recirculation button, so that the air drawn through the system is taken from the cabin and therefore already cool, rather than your aircon continuously having to cool down the hot air from outside.
To avoid the build-up of mould on and around the evaporator, which can lead to unpleasant odours coming through the vents and into the cabin, switch off your aircon, but leave on the blower, shortly before you reach your destination or at least before you turn off the engine.
A common misconception that many drivers have is that aircon is only for cooling down the vehicle’s occupants when it’s hot, when actually it can, and probably should, be used all year round, but particularly when it is cold or damp. This is because the air conditioning process also dries out the air entering the cabin, which means that it is very effective at clearing windscreens and surrounding glass of fogging from condensation.
But remember, whatever the time of year, always switch off the aircon, but not the blower, before stopping the engine.