Efficiency is one of the important things to consider when choosing household appliances, especially cooking equipment. Currently the community is starting to switch from from liquefied petroleum gas-based cookers to electric cookers. Therefore analysis is needed to determine the selection of electric cookers that are efficient in accordance with consumer needs. To accomplish this study, testing with boiling water was carried out on three types of electric cookers namely induction cooker, halogen and electric coil. This test is carried out to obtain input and output energy from each stove so that efficiency can be obtained. From the test results, it has been found that the induction cooker has the highest efficiency among the electric cooker.

The large amount of fly ash (FA) in Indonesia cannot be used optimally due to Government Regulation No. 101 of 2014 concerning Management of Hazardous and Toxic Waste which stated that FA was included in the category of hazardous and toxic waste. This study aims to conduct a study related to the effect of FA as fertilizer on plants. Five samples of FA obtained from five coal-fired power plants. They will be mixed with the soil by three different ratios: 25% FA:75% soil, 50% FA:50% soil, and 100% FA. This research used chilli, corn, and okra as the seeds. The finding shows that most of FA samples can be used as fertilizer for some plants.