How to use air conditioning in the car
Knowing the basics of turning your air con on and off is one thing, but do you know how best to use it to maximise comfort and minimise fuel consumption? Below, we look at tips and tricks for getting the most out of your car’s air con system, not only in summer but in the winter months too.
Should car air conditioning be on all the time?
It’s fair to say that many people use their air conditioning more in the summer, as a result of hotter daily temperatures combined with better weather giving the opportunity to get out and about more often. But this doesn’t mean that you have to have your air con on all the time to feel the benefits.
You have two ways you can increase airflow in your car in summer: by using the air con or by opening the windows and allowing natural breezes to come in. You might think that using both at once is the best way to maximise airflow, but it’s more likely that the two will cancel each other out and put the system under strain.
This is because opening the windows allows warm air to enter the car, meaning the air con system has to work twice as hard to cool the air. It’s far more efficient to let the air con work in an enclosed cabin, or to turn the air con off and allow the movement of air through the car windows to cool you down.
So why bother having air conditioning, if you can just open the windows instead? Well, there are some circumstances where it’s better to open the windows and others where air con is the optimal choice. For example, if you’re somewhere that’s quite loud, it’s often preferable to shut the noise out by keeping the windows closed.
It’s also the case that, when you’re driving at higher speeds, having the windows open increases the drag force acting on your car. This means the engine has to work harder to maintain the same speed, so you’ll likely use up fuel quicker.
Because of this, it’s usually recommended that you use air conditioning if you’re driving at speeds of 20 mph or more to conserve fuel. While the air con system works by using fuel, it’s generally less taxing to have the air con on at these higher speeds than it is to have the windows open.
However, when you drop to lower speeds or you’re stationary, the situation becomes reversed. When driving slowly, drag is less of a factor in fuel consumption, while the air con still uses the same amount of fuel. Therefore, whether you’re driving slowly through a neighbourhood looking for a certain address or you’re parked up waiting to pick someone up, it’s most efficient at these lower speeds to have the windows open instead of using the air con.
As we’ve mentioned, there is nuance to this as sometimes the environmental conditions of noise or air pollution may make it preferable to keep the windows closed. But it’s worth keeping in mind that turning off the air con when it’s not needed will save you fuel, and may even mean the system lasts longer without needing an air con recharge.
Does air conditioning demist the car?
While you’re much less likely to need air conditioning for the same purpose in the winter months, that’s not to say that it can’t be useful. In fact, finding uses for the air con in winter can also help to keep it in good working order, as long periods of disuse can account for a number of air conditioning problems as spring arrives. The most common way to use your car’s air conditioning during winter is to have it help out with demisting your windscreen.
Misty windscreens occur when warm air from inside your car comes into contact with the cold glass of the windscreen. Moisture in the air condenses onto the glass, which looks like mist and makes it difficult for you to see through clearly. When demisting, you turn on the heater to help warm up the glass so the moisture no longer condenses, clearing away the mist.
However, that moisture is still in the air. As soon as the windscreen cools, it’ll mist up again and you’ll have the same problem as before. This is where the air con comes in. By having the heater and the air con running at the same time, you can clear away the mist and remove the moist air from the cabin. Air from the air con system will be drier and less likely to result in a misty windscreen.
Of course, just like in summer, you can open the windows instead of using the air con to demist your car. However, this might not work as well if the weather is wet or humid, and you’re likely to get colder with the winter air coming in. Plus, the same speed guidelines apply in winter for deciding whether or not to use the air con, so if your windscreen mists up while you’re driving, air con may be the better choice.
Air conditioning can be useful for more than just keeping you cool in summer. If you’re at all worried about your car’s air conditioning system or you’re wondering whether it’s due for a recharge, get in touch with your local autocentre today.
