All four models have the same heating capacity 6,500 BTU (1.9 kW) low to 16,250 BTU (4.8 kW) high. The fuel consumption is per 24 hours: 4.8 litres (low) and 12 litres (high). Your choice of heater will be determined primarily by the space available and, of course, what appeals to you. These diesel heaters fit well in vessels of 30 to 60 feet (9-18 m) or for heating up cabins of 1,400 to 2,800 cu ft (40-79 m³).