What is a kilowatt-hour (kWh)?

In order to determine how much electricity costs, we also need to understand how it is measured. Electric companies charge their customers by the kilowatt-hour, or kWh.

1 kilowatt = 1000 watts

A kilowatt-hour, then, refers to the use of an electrical device or combination of devices that use 1000 watts over an hour of time.

For example, a 100 watt light bulb that is on for 10 hours would equal one kilowatt hour, or 1 kWh. Similarly, a 1500 watt portable space heater will use 1500 watts in an hour or 1.5 kWh.

To determine the cost of operating it for the winter season, consider a typical Connecticut household may use the heater 45 hours during the winter months (1/2 hour per day for three months):

Assuming an average electric rate of 16.95 cents per kilowatt-hour (kWh), we would calculate:

1500 watts/1000 = 1.5 kWh x 45 hours x 16.95 cents = $11.44

To calculate the average operating cost for any electrical appliance you can use the following formula:

watts/1000 = kWh x hours of operation = kWh x kWh rate = cost

Watts can usually be found on the appliance nameplate. If the nameplate lists amps, just convert to watts using the formula:

volts x amps = watts

To save money on home energy costs, it is recommended to replace old or outdated appliances with ENERGY STAR appliances. Your actual operating costs will vary by model, year, and wattage ratings, as well as actual hours used. Connecticut Light & Power offers a nifty energy calculator tool, which allows you to calculate the exact cost of operating certain appliances in your home.

Purchasing an energy meter, such as a KILL A WATT device below, will allow you to determine your actual costs based on the electric usage of the appliance. P3 International manufactures a very good electricity usage monitor with a graphic timer display. Simply click on the link below to get yours and start killing more watts!

Related Posts:

1. What Is a Time-of-Day Rate?

Tagged as: Electricity, Energy Conservation