fuel economy

How to Get the Best Fuel Economy in the Summertime

We’re all looking for easy and effective ways to improve our fuel economy. In the summer, though, we also need to stay cool – which often means opening the window or turning on the air conditioning, both of which increase fuel use.

Let’s compare the two cooling options to see which offers to best of both worlds.<?p>

Method 1: A/C On

First up, let’s consider how air conditioning works. The A/C in your car works by compressing a coolant that chills the air before it is circulated through the car. The compressor is activated by the same belt that powers your car’s alternator (which keeps your battery charged when the car is moving), and its energy comes from the fuel in your gas tank. That’s why the A/C only produces cold air when the engine is running; without the power to move the belt, the compressor won’t be able to cool the air and your fans will just re-circulate ambient air.

Method 2: Windows Down

Instead of using your car’s A/C, you could also just roll down the windows to let the air flow cool you. Doing so uses no extra gas in theory, although it does produce air resistance (a.k.a. drag) by making your car less aerodynamic. This effect increases with speed – the faster you go, the more drag will be produced by open windows. It is also more noticeable in smaller vehicles; bigger vehicles like trucks and SUVs produce quite a bit of drag on their own (because of their large size), so the effect of open windows is not as noticeable as in smaller, more aerodynamic vehicles like sedans.

The Verdict?

The jury is still out on this one: the best choice for optimal fuel efficiency depends on a huge number of factors, including the type of vehicle, your speed, the type of driving (city vs. highway), how high you’ve got the A/C vs. how many windows are open, etc.

To help you decide, here are some important things to consider:

  • At most speeds (and during city driving), rolling down the windows is the better choice for fuel economy, so avoid using A/C in these situations.
  • Even at higher speeds, opening your windows is likely still more fuel efficient than running the A/C – especially in larger vehicles.
  • A/C actually cools the air, while the open-windows approach relies on air flow for coolness. This means that on very hot days, or when you’re stuck in heavy traffic and not moving, A/C may be the better choice for comfort, regardless of its effect on your fuel efficiency.
  • A/C works more efficiently when your car is moving, so avoid using it when idling to decrease its effect on your fuel consumption. Also avoid using a colder setting than you actually need; turning your vehicle into an ice box won’t do you any favours at the pump.

Other Ways to Beat the Heat

  • As much as possible, drive during the cooler hours of the day (earlier in the morning and later in the evening), or at least avoid the hottest times of the day (usually between 10am and 2pm).
  • Using your sunroof causes less drag than opening all of your windows, so consider starting there if you can.
  • When you stop, do your best to park under trees and out of the sun, and use a sunshade to reflect sunlight away from your windshield.


Maximizing fuel economy involves balancing a large number of considerations, but when it comes to staying cool there are easy ways to beat the heat without breaking the bank. Use the A/C when you must, but try other cooling methods first if fuel economy is your biggest priority.





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Rick Wadhams

Rick Wadhams

As co-owner of Wadhams Enterprises, Rick has spent his life and career in the freight business, with experience in everything from maintenance to driving to management. Rick takes particular responsibility in overseeing the petroleum and milk divisions of Wadhams. His committment to seamless process, teamwork, integrity and support, coupled with the fabulous family atmosphere at Wadhams has helped grow Wadhams' reputation as the "Carrier of Choice, Employer of Choice."