Wondering how much energy your aquarium is consuming each month ? This is the Fomula to calculate ; For eg. Product A has Power Consumption of 10 Watts Product A Power Consumption : 10 Watts/1000 = 0.01kWh 0.01kWh X No. of hours used per day X No. of days used in a month = (Value)kWh Amount to be paid per month = (Value)kWh X Tariff rate Current New tariff rate from SP Services with effective from 01st July is 19.28 cents/KWh