2kW or 5kW diesel heater? If you're wondering between the two common choices of diesel heater sizes—2kW or 5kW—as mentioned above, it all depends on the length of your caravan. A 2kW heater will work well for a vehicle 21 feet or shorter, and a 5kW heater is best for caravans 24 feet or larger.

Diesel heaters are widely used and considered to be very safe. They include an auto-shutdown if the system temperature exceeds a safe operating level, the same as LPG heaters.

It uses an average of 0.16-0.48 liters of diesel and 36 watts of power per hour.

A 2kW diesel heater should be just fine for most vans. If you have a large van which you plan to use in really cold conditions, a 5kW diesel heater may be the better choice. In a house with good insulation, one sizes the heater to be about 1 kilowatt (KW) per 14 cubic metres of living space.