Calculate the cost. Ever wonder what it costs to run an appliance all year? It’s easy to figure out, just use this formula: Multiply the appliance’s wattage times the number of hours used per day times the number of days used per year. Divide the product by 1,000 to get the number of kilowatt-hours used annually. Then multiple the number of kilowatt-hours by your electricity rate in $/kilowatt-hour (typically around $0.12 per kWh).
For example, by not turning off your computer each night, you may be costing yourself (150 watts X 16 hours X 365 days per year)/1,000 * $0.12 or $105.12. More if you don’t turn off your monitor or printer either!