One Source Equipment Rentals has portable, temporary kerosene heaters for rent or sale from Heat Wagon. Indirect fired heaters use a separate heat exchanger to heat the colder air. Unlike direct fired heaters, indirect fired heaters can be used either inside or outside. When used indoors they require the fumes (carbon monoxide and water vapor) be vented outside. Air quality and moisture are not an issue with indirect fired heaters. These heater can use #1 & #2 Diesel, Kerosene, JP-8, or Jet A as a fuel source.