How long should you let the engine pre-heater be on before starting the car?

How long you should let the engine pre-heater be on before starting the car depends on what the temperature is outside.

Connection times

• Below -15 °C: 1.5 hours pre-heating
• 0 °C: 1 hour pre-heating
• 10 °C: 30 minutes pre-heating

Engine pre-heaters should not be used at temperatures above +10 °C.

Using an engine pre-heater is a simple way to minimise negative environmental effects. A preheated engine consumes less fuel than a cold one and also produces a smaller amount of exhaust emissions. During short journeys, especially, there is a big difference between driving away with a cold and a hot engine.