The researchers compared the efficiency of boilers using two types of fuel: commercial sawdust briquettes and biomass briquettes made from coconut leaves and sawdust. They found that the boiler efficiency was higher for commercial sawdust briquettes due to their higher calorific value. However, the coconut leaves briquettes had lower ash content and moisture, making them more environmentally friendly. The coconut leaves briquettes were also more economically viable as they are readily available.