AAA Offers Tips to Stay Comfortable During Extreme Heat

During extreme summer heat, a properly operating vehicle air conditioning system can be more than just a pleasant convenience. Maintaining a comfortable driving environment reduces fatigue, which can play an important part in driver alertness and vehicle safety.

AAA is reminding motorists that while your air conditioner can make driving in the heat more comfortable, it does come at a cost. Under very hot conditions, running your car’s A/C can lower your fuel economy by upwards of 25% (particularly on short trips), according to the U.S. Department of Energy site FuelEconomy.gov.

But there are things you can do to reduce its impact while staying cool. AAA offers the following tips to get the most out of your car’s A/C while protecting your fuel efficiency.

Shade and vent. When looking for parking, seek out shade and take proactive measures, such as setting up a sun shade on the windshield to keep warming UV rays out. That way when you return to the car, the cabin isn’t a sauna that requires even more energy to cool.

Roll down the windows first. Let the hottest air escape first so A/C doesn’t work as hard. If it feels unbearably hot in your car, your first instinct might be to crank up the air conditioning and pre-cool your vehicle before hitting the road. But that’s not an ideal move for fuel-efficiency if you have a gas or hybrid car. Unless you are charging an EV and it can draw on the external power, it’s not more efficient to pre-cool with the air conditioner. Plus, your A/C actually works better and will cool the car faster when you’re driving.

“When you first get into a hot vehicle, roll down the windows, if it’s safe to do so. Then while driving, turn the fan on your climate control system on the fresh-air mode to help the hot air escape,” said Ben Perricone, AAA Approved Auto Repair Territory Manager. “Running your air conditioning to cool your car down reduces fuel economy.  Resist that urge, unless health conditions require it.”

After a few minutes of driving and allowing the hottest air to exit the vehicle, roll up your windows and switch to A/C. At that point, the added drag from having your windows down may outweigh the potential efficiency savings.

Recirculate, with an exception. The recirculation setting on your air conditioning can make it more efficient because it means the system is cooling already treated air, but there are cases where it’s best to avoid it. One such instance is if you have passengers in the back.

“Do not use the recirculation feature if you have rear passengers as this will leave the rear passengers warmer than the front driver and passenger,” said Perricone.

Change your cabin air filter regularly for better air flow. Many automotive climate control systems today are equipped with a cabin filter that prevents outside dust and debris from entering. If present, this filter should be inspected and replaced as needed to ensure maximum airflow and cooling during the summer months. For SUV’s and vehicles with dual zone (rear) A/C, ensure both zones are active and cooling to increase cooling capacity and performance.

Check and maintain coolant and A/C system regularly. Vehicle engines work extra hard in the summer and it is the cooling system’s job to protect the engine from overheating. In addition, additives in the coolant protect the radiator and internal engine components against wear and corrosion. However, over time, coolant becomes contaminated and its protective additives depleted.  

Without proper cooling system maintenance, the odds of long-term engine damage, and a summer time boil over increase. Flush the system and replace the coolant periodically as recommended by the vehicle manufacturer. See the owner’s manual to determine the service interval appropriate for your vehicle.

Between flushes, make sure to fill coolant to the proper levels by checking the overflow reservoir. If necessary, top off the reservoir with a 50/50 mix of water and the coolant type specified by the vehicle manufacturer. 

CAUTION! Never remove the radiator cap when the engine is hot – boiling coolant under pressure could cause serious burns. 

“If a car’s air conditioning is not maintaining the interior temperature as well as it did in the past, it may mean the refrigerant level is low or there is another problem,” Perricone said.