Vehicle air conditioning

Air conditioning uses fuel

Using a vehicle’s air-conditioning system increases its fuel consumption more than any other auxiliary feature.

An air-conditioning (a/c) system can increase fuel consumption by up to 20% because of the extra load on the engine. The actual load depends on the vehicle’s interior size, the outdoor temperature and other conditions.

Be careful, even in winter

In winter, vehicles use heat from the engine to warm the cabin air. However, if you use the defrost setting, the a/c system may also be engaged automatically to keep the windows from fogging.

Manufacturers are developing more efficient a/c technologies, such as electric a/c systems, so that their vehicles will use less fuel.

This table lists the estimated fuel costs and CO2 emissions associated with a/c use.
Annual distance
driven using a/c
Annual increase in fuel consumption
with a/c use
Fuel cost of a/c use over 10 years* CO2 emissions from fuel used for a/c over 10 years**
If your a/c uses
1 L/100 km
If your a/c uses
2 L/100 km
If your a/c uses
1 L/100 km
If your a/c uses
2 L/100 km
If your a/c uses
1 L/100 km
If your a/c uses
2 L/100 km
14,000 km 140 L 280 L $1,400 $2,800 3,220 kg 6,440 kg
12,000 km 120 L 240 L $1,200 $2,400 2,760 kg 5,520 kg
10,000 km 100 L 200 L $1,000 $2,000 2,300 kg 4,600 kg
8,000 km 80 L 160 L $800 $1,600 1,840 kg 3,680 kg
6,000 km 60 L 120 L $600 $1,200 1,380 kg 2,760 kg

*Based on a fuel price of $1.00/L of gasoline.

**Based on a CO2 emissions factor of 2.3 kg/L of gasoline.

How to keep cool and use less fuel

With more than 20 million passenger vehicles on the road in Canada, the potential for savings from reduced a/c use is substantial. Here are some tips you can use to reduce.

Turn it off

Consider whether you really need the a/c for cooling. Just as you would at home, adjust your thermostat settings. Aim for comfortable, not cold.

Let the air flow

Use the flow-through ventilation when you’re on the highway, and open your windows and sunroof while driving in the city.

Hit the re-circulation button

Use the “re-circulating” function of your a/c system. This uses less energy because you’re cooling only the air already in your vehicle, not bringing in warmer outside air to be cooled.

Find a little shade

Your vehicle will need less cooling from the a/c at start-up if it’s parked in the shade. If you can’t find a shaded area, use window shades to reduce the heat when your vehicle is parked. Also, don’t use the a/c when you first start your vehicle. Instead, open the windows for the first few minutes and allow the hot air to escape.

Shut the a/c off after the windows are defrosted

In newer vehicles, the defrost setting automatically uses the vehicle’s a/c system to keep the windows from fogging. After the windows are clear, turn the a/c off and adjust the heater settings.

Be a knowledgeable buyer

When you shop for a new vehicle, be sure to ask which models have an a/c system with an “econo” mode or smart controls that help reduce fuel consumption.