Heating is normally provided using indirect diesel fired heating which sit outside the marquee and blows hot air through ducts. If the marquees are within confined spaces e.g. within factory units or sheds then electric heating can be provided instead. All heaters are thermostatically controlled and can be run off bulk tanks to ensure plentiful supply of fuel.
Heating can be distributed throughout areas that have been divided up to ensure an even spread throughout or incorporate any additional heating requirements e.g. to ensure that costumes can be dried overnight during periods of wet filming or to keep specialist costumes at an ambient temperature.