Does Car AC Use Gas?

You turn your car AC on during a hot week. And by the end of the week, you notice that your tank seems lower than usual. You know you had the AC on a lot this week, and you wonder, “Does car AC use gas like that?” The answer is yes! Your car AC system does consume fuel, and your alternator powers many of your car’s features–including your AC. What powers your alternator though? Your engine. Learn more about this process below as we discuss some good, general ways to improve your fuel efficiency.

How Does Car AC Work?

From Raleigh to Holly Springs, your AC system works the same way, and it’s important to keep in mind how heat and cold work. Cold is the absence of heat, and AC systems remove heat, blowing out cooled air. The cool air that we feel coming from an AC unit is air that’s had its heat removed.

All vehicles use a high-pressure gas referred to as a refrigerant to power the AC system, and that refrigerant is moving constantly through this system when turned on. Here are the parts that make up an AC system:

• Compressor – Compressors do just that– they compress a gaseous refrigerant into a fluid that flows freely to the condenser.
• Condenser – A condenser lowers the refrigerant’s temperature and sends it to the expansion valve/orifice tube.
• Expansion Valve/Orifice Tube – This reverts a refrigerant back into a gas, delivering it to the receiver/drier (the accumulator).
• Accumulator – The accumulator lowers the moisture content of the refrigerant, delivering it to the evaporator.
• Evaporator – The evaporator extracts heat from the air that passes through its core, transferring the heat to the refrigerant. This makes the cooled air flow from the evaporator.

Is Using AC Fuel-Efficient?

Using your AC is fuel-efficient when you’re at high speeds, like when highway driving. Having your windows down at highway speeds makes your engine work harder. This is because you’re exacerbating your car’s aerodynamic drag, and your car needs to use more fuel to move faster. 

Think of the shape of your windshield and notice how it’s angled up towards the top of your vehicle. Your vehicle is partially designed like this to reduce drag, having air flow over your vehicle instead of against it. Air is always moving against your vehicle, but this design helps lessen drag. Having your windows down adds more drag that your vehicle has to compete with, using more fuel to propel forward. Your city driving is also affected by drag– but to a much lesser degree.

How Can I Improve My Fuel Efficiency?

Your car AC uses gas, but there are some practical ways of improving your gas mileage. Besides keeping your windows up while on the highway, here are some great tips from our service department:

• Keep your vehicle up to date on maintenance. Your driving habits pale in comparison to dirty oil or sparkplugs, old tires, or other physical components that need to be replaced.
• Keep necessary supplies in your vehicle, but don’t use your vehicle as a storage unit if you’re able. More weight means more fuel is needed to propel your vehicle forward.
• Use high-quality engine oil.
• Ensure proper tire alignment and inflation.
• Avoid unnecessary idling, like when parked at home or in a parking lot.
• Reduce your speed and drive in a higher gear.
• Brake and accelerate gradually instead of quickly.

Find a Fuel-Efficient Vehicle at Hendrick Buick GMC Cary!

If you have any more questions about fuel efficiency, be sure to contact us today online or call us at (919) 342-8196 to have your questions answered by our knowledgeable staff. We offer a variety of service specials for Apex drivers and beyond!