Air conditioning and cabin heating

Air conditioning and cabin heating affect more than just comfort. Proper use provides better visibility, lower fuel consumption, and safer driving. You may encounter questions about this on the theory test.

Functions of the air conditioner

Fog and visibility

One of the most important reasons to use the air conditioner is to remove fog from the windows. Moist air in the cabin condenses on cold windows and drastically reduces visibility . To avoid fogging:

• Turn on AC to dehumidify the air, even in winter
• Use the defrost function aimed at the windshield
• Avoid drying clothes or having wet items in the cabin
• Ensure the cabin filter is not clogged

Fuel consumption

The air conditioner is powered by the engine and increases fuel consumption by 5–10% during active cooling. To save fuel:

• Use AC only when necessary
• Park in the shade during summer
• Vent hot air by opening windows briefly before turning on AC
• Read more about fuel consumption and CO₂

Electric car and cabin heating

In an electric car , cabin heating is powered by the battery, not engine heat. This means:

• Heating can reduce range by 10–20% on cold days
• Many electric cars have a heat pump which is more efficient than pure resistive heating
• Preheating while the car is charging saves battery

Cabin temperature and concentration

Too high or too low temperature in the cabin negatively affects concentration. A comfortable temperature around 20–22 °C is ideal. Warm, heavy air can make you sleepy, which is dangerous on long trips. Fresh air and the proper temperature are part of eco-friendly driving and safe driving.

Maintenance

• Replace the cabin filter according to the manufacturer’s recommendations
• Run AC for a few minutes at least once a month, even in winter, to keep the system lubricated
• Have the air conditioner checked at EU inspection or at a workshop

Further reading

• Visibility and windshield wipers for fogging tips and window care
• Fuel consumption and CO₂ about what affects consumption
• Electric and hybrid cars in traffic about range and heating
• Daily vehicle check for an overview of daily checks