What is the highest temperature at which it is efficient to use engine pre-heaters?

It is efficient to use engine pre-heaters at all temperatures up to +10 °C.

Engine pre-heaters should not be connected for longer than recommended, as that would only result in unnecessary energy consumption.

Connection times

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