You can buy diesel heaters for caravans, they seem to use about 0.6-0.7 litres/h...

		caf on Jan 5, 2022 \| parent \| context \| favorite \| on: Motorists have been stranded on a major interstate... You can buy diesel heaters for caravans, they seem to use about 0.6-0.7 litres/hour (eg. this sort of thing: https://www.amazon.com/dp/B07K1JJ92S/ ).