Learn about energy efficiency

Check out a Kill-A-Watt meter to learn more
about your energy usage

By Suzie Romig
Clean Energy Economy News

On a recent sunny Sunday afternoon, my choices were to continue toiling on never-ending yard work or play with the Kill-A-Watt electricity usage meter I checked out from the local branch of the Garfield County Library.

Garfield Public Library District

Kill-A-Watt meters are available for check-out at all branches of the Garfield County Public Library District

Locations and hours of your public library

My curious side overpowered my industrious side, and I realized this would be a great opportunity to learn more about our household power usage.

I wanted to try to answer some nagging questions in my ongoing efforts to decrease my home energy usage and lower the electric portion of my Xcel bill. Such as, should I unplug the microwave when we go on vacation? How much power does the warm-to-the-touch television receiver box use? Is it greener to buy battery-powered or electric clocks?

And the most important question, will I have to do math to figure this all out?

The written instructions provided with the meter were easy to follow. However, the booklet advises that to test an appliance that is used every day, the Kill-A-Watt should be used for a full hour.

So, note, reserve a few days or evenings to monitor a variety of appliances in your home or office. Find a timer and grab a calculator to start the experiment.

To save time, I decided to prioritize and test the things that I could change, unplug or replace.

Kill-A-Watt in actionFirst, I tested our nine-year-old GE microwave. After the microwave cycle finished, I pushed the purple button on the meter to learn that my microwave used .07 kilowatt hours (kWh) in three minutes. I used the Colorado average cost of electricity of 8 cents per kWh. Using the formula supplied in the instructions, I calculated this cost for using our microwave oven:

Microwaving at 0.07 kWh X 5 uses per day = 0.35 kWh X 30 days per month X $.08 energy costs = $0.84 per month

So, using our 1,500-watt microwave for only short bursts of time costs less than one dollar per month, which is well worth it for our on-the-go, culinary-challenged family. Buying a newer, smaller microwave is now off my wish list, especially because lots of energy and materials are used to manufacture and ship new household products.

Energy auditors advise consumers to know which are the highest wattage items in your home, such as a space heater, and try to limit the time those appliances are used. I used the same formula on another high-wattage item, the bathroom space heater. In the 25 minutes I ran the heater, it used 0.11 kWh. The month calculation looks like this:

Bathroom space heater at 0.11 kWh X 2 uses per day = 0.22 kWh X 30 days per month X $.08 = $0.52 per month

Therefore, it’s acceptable to use my Honeywell heater for shorter periods for a toasty bathroom, but it would be inefficient and costly to run it for 8 hours a day to heat a room.

Even lower wattage items can be energy and money hogs if accidentally left on for many hours. Common culprits are heat tape, lights and electronics, so think about using program modes, plugging the device into a timer or installing motion sensors on light switches.

Kill-A-WattThe Kill-A-Watt meter also is a great way to determine the wattage an appliance is pulling. Simply plug the appliance into the meter and hit the watt button.

Consumers can estimate how much they spend to run appliances by knowing the wattage and the amount of hours per day the appliance is used. According to the energy auditor at Holy Cross Energy, another simple formula to use if you know the wattage of a device is:

Watts X number of hours X 30 days per month ÷ 1,000 = kilowatt hours used per month X $.084 power cost = cost to use the device each month

I’m no engineer or energy auditor, so I compared the wattage of various appliances to a basic item I could understand, a 13-watt compact fluorescent bulb. For example, one Direct TV receiver box draws about 10 watts and is left on 24 hours a day to maintain the satellite signal. So with our two receivers on all day every day, that uses more power than leaving a CFL on 24 hours a day 365 days a year.

I have more items to monitor, from clocks to televisions, but what I discovered is that learning more about household power usage is interesting. When I visit the library next time, I will put a Kill-A-Watt meter on hold again. The more I learn, the more I can work to alter my energy-use habits and prioritize purchases of Energy Star appliances.