Your car’s air-conditioning system has one job—to keep you cool. But during a summer scorcher, it may seem like it’s barely up to the task. And even at those times, it’s eating up gas: The EPA estimates that using A/C in very hot conditions can reduce fuel economy by as much as 25 percent for a conventional vehicle. (It also zaps battery life in electrics and hybrids.)
Here’s why: Whenever you flip the switch, the system pulls in air from either the cabin or outdoors, extracts the heat and moisture from it, and pushes it out through vents. And the heart of this system is a compressor, which draws energy from the engine. So whenever you’re using the A/C, the engine has to work harder—and you burn more fuel.
But a few easy tips can help you save gas—and money—while making you feel cooler faster. Here’s what the pros recommend.
Park Smart
A car’s A/C system can only reduce the cabin temperature by approximately 40 degrees on average, says Jill Trotta, head of industry advocacy and sales for RepairPal. (Though of course, the longer you drive, the cooler the air will become.) If you park in a shady spot, the interior will start out cooler and the A/C will have less work to do. If the cabin is warm, roll down the windows and let the hot air escape before you rev up the A/C.
Set It To Recirculate
“Recirculation is probably the best way to maximize the A/C,” says Trotta. The benefit of recirculation is that the A/C system is pulling air only from within the cabin. So if it’s roasting outside but you already have the cabin down to a pleasant 72 degrees, the A/C will have to chill only that cooler air within the car. You’ll save on gas, too: Once the interior reaches the set temperature, the A/C compressor will turn off, reducing the load on the engine.
Skip Pre-Cooling
It may be more comfortable to cool your car before you’re underway, but running the A/C when the car’s not moving is highly inefficient. “Air conditioning will perform optimally when there’s airflow, like when you’re driving down the road,” says Timothy Hatcher, director of technical operations for the Automotive Maintenance & Repair Association. So wait until you’re already cruising before you turn it on. In an electric or hybrid, pre-cooling reduces the battery life, so either avoid the practice or stay plugged into the charger when you do it.
Change Your Cabin Air Filters On Schedule
The cabin air filters remove dirt and dust from the air that comes out of the vents. When a filter gets dirty, it restricts the air trying to pass through, says Hatcher. So replace the cabin air filters according to the schedule in your owner’s manual, which is probably every year or two, or every 15,000–20,000 miles.
Don’t Ignore Leaks
The biggest misconception about A/C systems, says Hatcher, is that if they’re low on refrigerant, you just need to add more (a process called recharging). But the system is sealed; nothing should be going in or out. “Adding refrigerant isn’t normal, and it isn’t maintenance,” says Hatcher. “It’s an indication of some other issue.” If yours is low, visit a professional certified in air-conditioning maintenance and repair to check it out.
Another way to keep your cool (and peace of mind)? Download the GEICO Mobile app for help at your fingertips—from roadside assistance to help finding your car and more!
Read more: Check out these other smart ways to get better gas mileage.
By Julie Anne Russell
Meerkat Brzezinski says,
Surprised by how many people read this article and were not thinking, “I just wasted a minute of my life on what should be common sense!”
Rosa M Flores says,
THESE CAR TIPS are the best messages I’ve ever received-hope there’s MORE to come!
Danny Sherman says,
Thank you….. very good information!!
Sharon Leary says,
Thank you for the tips o, my cars air conditioning. I didn’t know there was a filter to be changed. My Honda dealer probably has never done that even though I have 42,000 miles on my car. I will check it out!
SASTRY NETI says,
Thanks.Very helpful.
How do I recirculate the cooled air ?
Kathleen Katkowsky says,
Thanks for great tips and reminders
David R. Aiken says,
Thanks for the AC tips. There was one of them I had never heard before, but I will definitely keep it in mind for the future.
Keep up the good work and thank you for looking out for my wallet.
LOIS HERNANDEZ says,
THANK YOU SOME OF THE THINGS I DID NOT KNOW
lois hernandez says,
i want to thank you for that advice i didnt know any of that
Eliseo Alvarez says,
Buenas recomendaciones, cosas que yo no hacia por desconocimiento, gracias por la ayuda y envien mas consejos,gracias.
Kandis Slockbower says,
Thank you for the tips and reminders for keeping our car cooler and save on gas and battery power. It is good for me to keep up on all information with the good tricks to be more efficient with everything that I do for me and the planet that we live on! Sincerely, Kandis
Marcy Caldwell says,
I live in Redding, CA where the CARR fire and several others are still not totally maintained.
The ashes are mostly gone but the smoke is such that weldon’t see blue sky. I have heard it is good to replace a filter that lies at back of glove compartment? Are there others to replace. My A/C is getting worse each day 0 wears have 100+ heat.
Any suggestions?
CELESTE I GARCIA says,
I usually crack window open a tad DURING day. Then I start my car with windows open let hot air out.
Then I will turn on the air-condition. I always turn off air-condition before I turn off car. Its a good way not to burn out parts in your a/c.
Ronora Smalley says,
Thank you so much for the information, it is greatly appreciated. I was always told that the air conditioning has nothing to do with the ⛽ gas although I myself would always see the gas deminish, it’s nice to see something in writing .
Thomas Brown says,
I use recirculate often, but NOT when I first enter the vehicle. Sitting in the hot sun makes the interior temp 10+ degrees hotter than outside temps, so why recirculate the hotter air? Better to crack the windows, let the ambient air flow through, and when the interior temp is normalized, turn on the recirculate.
Josefina Huerta says,
Should AC be shut off after using car .
kevin says,
Absolutely. In fact, some junk Nissans will leave the compressor running even after you think you’ve shut it off. Especially if you go into defrost mode. So be aware.