Fuel Economy and Running AC Myth

Fuel Economy and Running AC Myth

The price at the gas pump can vary month to month, but the general trend has been upwards over the past few decades. This increase can be a significant chunk of the monthly budget for individuals who need to drive regularly for work or errands. 

The fuel economy or efficiency that our vehicle operates at is vitally important to our bottom lines. The estimated and actual gas mileage that we get with cars is a significant deciding factor in what we buy. But other factors outside of engine design can have an impact on our wallets.


Does Running the AC Tank My Fuel Economy?

When warmer weather hits, the age-old debate about running a car AC in hot weather always seems to kick off. But will running the AC in your vehicle really decrease the fuel economy? 

The unfortunate answer is that air conditioning systems tend to lower fuel efficiency in most vehicles. It simply has to do with how cooling systems work. 

Vehicle air conditioning is a closed system of gas coolants undergoing thermal exchange. At the core of this system is the AC compressor. This device attaches by belt to the engine's crankshaft and relies on its power to pressurize the coolant system. 

Anytime the AC is running, it takes a bit of the engine's power. However, the extent to which you will notice depends on several factors.

  • Outside Temperature: The hotter it is outside, the harder the cooling system needs to work, and the more power it draws from the engine.
  • Trip Duration: Conditioning systems are more efficient over longer trips and are most efficient when the car is moving. Maintaining temperature is always easier than drastically changing from hot to cold.
  • Vehicle Type: Large SUVs have a greater volume of air to cool and will feel the most significant drop in fuel economy. While newer cars tend to have more efficient cooling systems, electric vehicles and hybrids can take the largest hit to drive range from running AC.

For most individuals, the effect of running the cool air might amount to less than a 3% reduction in fuel efficiency. In reality, a handful of pennies at the pump. 

Tips for Better Fuel Economy 

If you find yourself needing to use the AC in hot weather and are concerned about your vehicle, there are a few tricks that can help reduce the stress on your AC system and limit the effect on your gas mileage.

  • Open Windows: Unless you are going top-speed on the highway, an open or cracked window will have less impact on fuel efficiency. So if you just need air movement, this may be a great solution.
  • Wait: Since HVAC systems work better when moving, skip or use a lower setting when in the vehicle for only a few minutes. And for longer trips, crack windows at the start to vent the hottest air directly outside.
  • Maintain: If it seems like your car isn’t getting or staying as cool as expected, don’t just crank up the dial. Get the system checked by a technician to ensure there isn’t an issue with coolant levels, fans, or the compressor. Poor maintenance is the easiest way to lower gas mileage.

How to Improve Fuel Efficiency

During summer, hot weather and air conditioning might make you think about your car's fuel economy. But you can take many other actions to help get the best gas mileage out of your vehicle throughout the year. 

1. Determine Your MPG

Most vehicle models come with estimated miles per gallon. Your driving habits and conditions can leave you with a vastly different number in reality. The easiest way to determine if you are having an issue with fuel economy is to determine the number of miles you get out of a tank.

Next time you fill up, note down how many gallons it took to refill and your odometer reading. Refill when you reach the same fuel level and note the new mileage. Subtract your odometer readings to figure out how far you have driven. By dividing the gallons you used by the distance, you get your MPG. 

You can repeat this process over a few weeks of everyday driving to get an accurate record of your fuel efficiency. If you are averaging 44 MPG or more, congrats, you have some of the best fuel efficiency around. If you are regularly getting less than 20 MPG, your vehicle is on the lower scale of fuel economy rating, and you may need to look into why it is so low. 

2. Driving Habits

Studies show time and again that aggressive driving considerably lowers your fuel economy. Frequent speeding up and slowing down along with high speeds causes your engine to work overtime, eating up gas. If you regularly drive on the highway, switching on cruise control can keep you at a safe, steady pace and eke out a few more miles per gallon on your commute.

For those who drive through towns and cities, the stop and start nature of traffic can seem unavoidable. If you can, plan a route that involves fewer stop lights or intersections. It might increase distance, but it will improve fuel economy. And you never know, skipping the regular high traffic routes might get you a few minutes back to your day.

3. Proper Maintenance

Even a highly rated fuel-efficient car on the lot can quickly become a gas guzzler if poorly maintained. Make sure to get your vehicle regularly inspected by a trusted mechanic. Things as simple as old or incorrect motor oil, underinflated tires, and dirty air filters can tank the MPG you get.

Trusted, Local Automotive Maintenance

If you notice issues with your vehicle’s AC system or think you might have experienced a significant drop in your fuel economy, you may be overdue for maintenance. With over 20 years in car repair, Jody’s Automotive Repair and Lube Shop have the experience you can trust to diagnose and fix your vehicle.

Located in Jonesville with access off US-21 and I-77, we are conveniently located to serve clients in Elkin and throughout Yadkin County. Contact us today to set up an appointment to get your vehicle serviced.