How much extra fuel or EV range does the air con cost?

The air con makes driving more comfortable, but it uses energy. How much depends on where and how you drive. Here you can read what the air con costs in a petrol or diesel car and in an electric car, whether windows down or air con on is more economical, and which habits help you save energy.

By the team at Autobedrijf Willemsbrug, RDW-approved APK (MOT) test station since 1979 · Updated 4 November 2026

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The short answer

According to a test by the German motoring club ADAC, a car with the air con on uses on average 10 to 15 percent more fuel. In town that is about 20 percent, roughly 1 litre per 100 km, and outside town about 6 percent, roughly 0.3 litres per 100 km. These figures apply to a car that normally uses 5 litres per 100 km, at 25 °C outside. An electric car also loses range through cooling and above all through heating: according to the Dutch independent information centre Milieu Centraal, range in winter is about 85 percent of the yearly average.

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How much extra fuel does the air con use?

On average the air con costs 10 to 15 percent extra fuel. That was the result of a test by the ADAC, the German sister club of the Dutch motoring organisation ANWB. The ADAC cooled a car from 25 °C outside to 22 °C inside. The extra consumption depends heavily on the type of journey:

Situation Extra consumption with air con In litres
In town about 20 percent about 1 litre per 100 km
Outside town (average 100 km/h) about 6 percent about 0.3 litres per 100 km
Stationary with the engine running about 70 percent about 0.4 litres per hour
Average over all journeys 10 to 15 percent varies per journey

Source: ADAC test, 25 °C outside, 22 °C inside, car with a standard consumption of about 5 litres per 100 km.

In very hot weather it can be more. The US Department of Energy writes on fueleconomy.gov that air con can cut fuel economy by more than 25 percent in very hot conditions, particularly on short trips. This applies to petrol and diesel cars alike, because in both the air con compressor is driven by the engine.

Why does air con cost more in town than on the motorway?

In town, driving itself takes little power, while the air con needs roughly the same amount of power as on the motorway. So the air con takes up a larger share of the total. On the motorway the car needs much more power to keep moving. The part used by the air con is then relatively small.

Short trips are the most expensive. On a short trip the air con first has to cool down a hot interior. That takes the most energy. Milieu Centraal therefore advises leaving the air con off on short trips, such as in town, because that is when it uses relatively much extra fuel.

Windows down or air con on: which is more economical?

At low speed, open windows are more economical. At high speed the difference is small and the air con can be the better choice. Open windows create extra air resistance (drag), and that drag grows quickly as you drive faster.

  • In town and on main roads: windows down is more economical. The drag at low speed is small.
  • On the motorway: the ADAC measured about 0.2 litres per 100 km extra with two side windows open at 80 to 100 km/h. That is close to the extra consumption of the air con outside town. Fueleconomy.gov advises rolling the windows down at lower speeds and using the air con at motorway speeds.
  • Combine both: first open the windows for a few minutes to let the hot air out. Then close them and switch on the air con. Milieu Centraal and fueleconomy.gov both give this advice.

Please note: the ADAC measurements for open windows and for the air con were separate tests. So this is an indication, not a direct comparison. Comfort matters too: with the windows open on the motorway it is noisy and draughty.

How much range does the air con cost in an electric car?

In an electric car, the air con reduces range instead of costing fuel. According to fueleconomy.gov, the effect in percentage terms is often larger in hybrids, plug-in hybrids and electric cars than in a petrol car. An electric motor uses little energy to drive the car, so the energy for the air con stands out more.

In winter it costs even more. The car then has to heat the interior and the battery works less well. According to Milieu Centraal, batteries perform best between 15 and 25 °C.

Season What uses energy What the source says
Summer Cooling the interior and often the battery as well Effect in percent often larger than in a petrol car (fueleconomy.gov)
Winter Heating the interior, cold battery Range about 85 percent of the yearly average (Milieu Centraal)
Freezing cold Heating and a cold battery Range up to 30 percent lower (ANWB)

According to Milieu Centraal, newer electric cars often have a heat pump. It heats the car using the same refrigerant circuit as the air con, but in reverse. How that works, and what it means for servicing, is explained on our page EV and hybrid air con in Rotterdam.

What does the air con cost in a hybrid or plug-in hybrid?

In plug-in hybrids and many self-charging hybrids, an electric motor drives the air con compressor. It takes its power from the high-voltage battery. A mild hybrid often still has a compressor that the engine drives with a belt. Then the same applies as in a petrol car. With an electric compressor the air con keeps cooling when the combustion engine is off, for example in a traffic jam or at traffic lights.

The result: on a hot day the combustion engine starts more often to recharge the battery. You notice a slightly higher fuel consumption and, in a plug-in hybrid, fewer electric kilometres. That is normal and not a fault.

How to use the air con efficiently

  1. Park in the shade or use a sunshade. The cooler the interior, the less work the air con has to do (fueleconomy.gov).
  2. Let the hot air out first. Drive the first few minutes with the windows open, then close them and switch on the air con (Milieu Centraal).
  3. Do not run the air con at full power. Choose a reasonable temperature instead of the coldest setting (Milieu Centraal).
  4. Use recirculation briefly. Recirculation cools faster at first, because the air con reuses air that has already been cooled. Do not leave it on for long: the windows then mist up more quickly and the air gets stuffy.
  5. Electric car: pre-cool or pre-heat while plugged in. The energy then comes from the grid and not from the battery you are about to drive on (ANWB and fueleconomy.gov).
  6. Winter: use seat and steering wheel heating. These warm you directly and use less energy than heating the whole interior (ANWB).
  7. Switch the air con off a few minutes before the engine. Milieu Centraal gives this advice. It also gives the evaporator behind the dashboard a chance to dry out a little, which helps prevent smells.

Does a poorly maintained air con use more fuel?

Yes. The ANWB writes that a poorly working air con has a negative effect on fuel consumption. The air con then has to work harder or longer for the same cooling.

Cause What happens
Too little refrigerant The air con cools less. The compressor runs longer to produce cold air.
Dirty condenser at the front of the car Leaves, insects and dirt trap the heat. The pressure rises and the compressor has to work harder.
Clogged cabin filter Less air gets through. You turn the fan up and the air con stays on longer.

Milieu Centraal advises using the air con at least once a month and keeping the vents free of leaves and dirt. If your air con cools less well than it used to, have it checked. What happens during a service is explained on our page car air conditioning service in Rotterdam. Does the air no longer get properly cold? Then read car air con not cold or blowing warm air. Our technicians hold the GMTO certificate (the Dutch qualification for working on high-voltage systems) for hybrid and electric cars.

Frequently asked questions

Does the air con use fuel when it is switched off?

No, hardly any. When the air con is off, the compressor does not pump refrigerant around. Only the fan still uses a little electricity.

Does the air con use fuel when the car is stationary with the engine running?

Yes. According to the ADAC, the extra consumption when idling is about 0.4 litres per hour. In percentage terms that is about 70 percent more, because the engine uses little fuel at idle.

Should I switch off the air con in winter to save fuel?

No. Milieu Centraal advises using the air con at least once a month. The air con dries the air, so the windows clear faster. Read more in misted windows? Switch on the air con, in winter too (in Dutch).

Does an electric car go further in summer than in winter?

Yes. According to the ANWB, a full battery does not take you as far in winter as in summer. In freezing cold, range can be up to 30 percent lower. Cooling in summer also costs range, but usually less than heating in winter.

Does a lower temperature setting use more energy?

Yes. The bigger the difference between outside and inside, the harder the air con has to work. Fueleconomy.gov writes that a slightly warmer setting uses less battery power in an electric car.

Does air con cost less in a diesel than in a petrol car?

No, not really. In both, the engine drives the compressor. In litres the difference may be slightly smaller, because a diesel is more economical, but the air con needs the same power.

How can I tell if my air con is using more energy than it should?

You notice that the air con cools less well than it used to, takes a long time to cool the car or needs the fan higher than usual. If so, have the air con checked. You will hear the cost in advance.

Is your air con cooling less well than it used to?

Call us with your registration number on +31 10 479 00 00. We will check whether your air con is working harder than it should, and we tell you the cost in advance.

You will find us at Boterdiep 11 in Rotterdam-IJsselmonde, close to Stadion Feijenoord (De Kuip). We work by appointment. For a quick question or check you can walk in without an appointment.

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