The document discusses calculating energy use and costs for various household appliances. It provides examples of calculating energy transferred in kilowatt hours (kWh) for devices like a computer, heater, and television based on their power and time of use. The total energy transferred for all devices is calculated as 7.1 kWh. Additional examples calculate energy transferred for a microwave oven, heater, and hairdryer used for specific durations. The total energy transferred for these is 4.7 kWh and the cost at 8p per kWh would be 37.6p.