The little-known AC button that will help slash your fuel bill & keep cars perfectly cool as temps soar this weekend

The Sun

13-06-2025

MOTORISTS might have missed this air conditioning setting that is essential for keeping costs down as the weather heats up.
With a warm weekend ahead and temperatures hitting 29C today as Brits head into the summer months, drivers maybe unknowingly wasting money in the fight to keep their cars cool.
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Many motorists might simply set their AC to full blast when trying to handle the heat, and while this will get temperatures down, it might be over-kill if you are travelling alone.
Instead, setting your vehicle's air con to 'driver only' will make sure that all the energy will be used on cooling just you down, rather than refrigerating those empty seats.
A vehicle's air conditioning can have a very negative impact on its fuel economy by putting a greater strain on its engine, according to The AA.
'Driver only' setting
The car insurance company has urged drivers to check if their motor has the 'driver only' AC option, and to make sure it is always in use when appropriate.
Air conditioning can increase fuel consumption by between 8 and 10 per cent, amounting to an extra 0.2 and 0.4 litres per hours, according to Kwik-fit.com.
It is also advisable to reduce the increased strain on the engine by turning the flow rate down once the AC has brought your car to a comfortable temperature.
Drivers should also avoid travelling at speed with the windows down, if they are trying to be as fuel-conscious as possible.
Driving with open windows can increase the drag on the vehicle, making the engine work harder to maintain speed.
Getting the instruments in your car regularly serviced is also key to keeping everything working efficiently.
Kwik-fit recommends ensuring that your air-con system is regularly regasssed to keep it running as efficiently as possible while using minimal power.
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It also lists ways in which drivers can cut down on having to use the AC at all.
Taking measures such as parking in the shade and opening windows when setting off can help keep the car cool without putting more stain on the engine.
Air Con not cold enough? Here are four checks you can do at home to save yourself hundreds
By Jorge Hinojosa Mena
A CAR expert has revealed four checks you can do at home if your air-con isn't cold enough.
Air Con expert, Andrew, from specialist firm Accelerate Off-Grid Touring says that these simple checks are essential to ensure your air conditioning is summer-ready - and it could save you a bundle of cash.
YouTube user @accelerateoffgridtouring, with more than 12,200 users on social media, explained that you should first check for any unusual noises in your motor.
Andrew explained: "On most cars, when you turn the air conditioning on, you should hear a loud click, and that's the noise of the air compressor cutting in.
"If you hear a rumbly sound once your compressor cuts in, this means it's on its way out, and you'd need a replacement."
Second, the car expert recommends checking for any weird smells.
"If there is a musty or unpleasant smell coming out of the vents or your allergy symptoms are being triggered when the air conditioning gets switched on, there may be a bacterial or mildew buildup in the system.
"The other thing that can happen is it can be a sign that your evaporator's leaking, so it's leaking as in the car. That's sort of an issue.
"The other thing you'll notice if your evaporator's leaking is the air conditioning will be low on gas, so it won't be as cold as it should be and will have that uneven vent temperature."
Andrew advises carrying out a performance test to make sure your air-con is in good condition.
He explained: "What we've done here is we've put a thermometer in the vent. You can just use any old thermometer.
"We've set the fan to first or second speed, and we've also got it on recirculate. That's quite important.
"What we should see is a temperature of below eight degrees. The temperature will fluctuate as the compressor cuts in and out.
"This is a natural part of the air conditioning system.
"What it will do is the compressor gets colder and colder and colder, as it gets down to a freezing point, so out here at the vents, it will say six degrees to five and a half degrees, the compressor will cut out, the temperature will rise to about seven or eight degrees, and then it will cut back in. The cycle will continue. It's called cycling."
The expert insisted that if you see the temperature going below five degrees, that's a sign that something is wrong.
He continued: "It's either gonna be faulty thermostat or thermistor, or more commonly, a blocked cabin filter."
Lastly, Andrew says drivers should be concerned if they see water under their car after driving with the air-con on.
The car expert added: "The air conditioning system was designed to drain the condensation to the exterior of the car. If you've driven for a long time, you pull up, and it will make a pool of water.
"The amount of water it discharges at the bottom actually depends on the humidity of the day and what setting you've got your air conditioning on, so don't stress too much about having the pool. You just want to see it on the outside of the car.
"One thing to look for is if the air con's cold, it's a humid day, and you do not have water on the ground outside of your car, maybe just check the passenger floor of your car 'cause sometimes that drain tube can block up, the water can leak inside the car, and obviously, then you get a mouldy, stinky carpet."
This comes after an expert mechanic revealed some of their top tips about air conditioning, including one which can cool down your vehicle very quickly.
Plus, an expert mechanic has revealed how to keep your car's air-con blowing ice cold-free.