Calculate Product Energy Consumption

Posted on 01-07-2016

With the New Year comes resolutions and finding ways to save money for your household and business. In order to save, you need to find out what appliances in your home or office are costing you.  Energy.gov gives the following steps in calculating annual energy consumption of an appliance.

1.  Estimate the number of hours a product runs per day.

For example, write down how many hours you watch TV per day, use the microwave or have the computer running.  When calculating a refrigerator which runs in cycles, divide the number of hours it's plugged in by three.

2.  Identify the wattage of an appliance.

You will find the wattage on the back of a product or on the nameplate.  The number listed is the maximum wattage power used by the item.  Some products will have a wattage range such as a radio which uses more wattage when the volume is louder.

Home Energy Saver provides a generic list with estimated energy wattage and annual energy use.  If your appliance is ENERGY STAR, you can go on their website to find the wattage of a particular appliance.

3.  Find the daily energy consumption with this formula:

(Wattage x Hours Used Per Day) ÷ 1000 = Daily Kilowatt-hour (kWh) consumption

4.  Find the annual energy consumption with this formula:

Daily kWh consumption x number of days used per year = annual energy consumption

5.  Find the annual cost to run an appliance with this formula:

Annual energy consumption x utility rate per kWh = annual cost to run appliance

Visit Energy.gov for examples and to use their Appliance Energy Calculator to estimate a product's energy use and annual cost to run it.