A dairy processing unit in a remote area needs to operate the generator 8 hours/day due to unreliable electric power supply. The generator consumes diesel but operates at an efficiency of 30%. About 70% of the energy released on burning the fuel is lost as heat, mostly through the exhaust. The dairy unit also requires hot water for which they have to burn additional fuel. Overall the fuel costs are very high. How can the unit save money on fuel costs, with minimum additional capital costs?