Kouba-Cavallo Associates, Inc.
Testing for Phantom Load


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What consumes electricity when you can not see it? It is a PHANTOM LOAD.

Your furnace is not running. Your air conditioner is turned off. You have turned off all the lights, TVs, and appliances (including humidifiers). You have even unplugged the water bed heater and fish tank. And yet the disk on your electric meter still turns. What's going on?

It may be the instant-on TV or all the clock radios in you house. It could be something totally unnecessary, but you don't know about it. It may be burning up your electric bill all day long throughout the year.

Here is a method for quantifying your home's phantom load. After you know the size of the unknown load, you will be in a better position to track it down, shut it off, and eliminate the pollution that results from its generation.

First, turn off all known loads.

Second, find four 60 Watt lights and turn them on.

Third, take a stop watch (or a watch with a second hand) and find out how many seconds it takes for the disk on your electric meter to make one revolution.

Fourth, write down the number of seconds it took.

Fifth, turn off one of the 60 Watt lights.

Next, repeat the third thru fifth steps two times with three and then with two 60 Watt lights on.

Now get back on this web site (Oh, by the way: did I mention to log off the internet and turn off your computer before taking your measurements?) and fill out the table below. You should have had 240 Watts of known load when you had four 60 Watt lights on, 180 Watts of known load when you had three 60 Watt lights on, and 120 Watts of know load when you had two 60 Watt lights on.

Click on "Compute" when you have filled out the table.

If your phantom load is greater than 40 Watts, you can likely find energy savings around your home. So go search for the PHANTOM LOAD.

Observation No.
Seconds for Disk to Revolve Once
Known Load
(in Watts)

The above tool is based on a method proposed by James Mapp, Ph.D., of the Wisconsin Energy Bureau. All errors in the implementation of this method are the responsibility of Jim Cavallo, and not the fault of Dr. Mapp or the Wisconsin Division of Energy. The use of this method does not imply the support or endorsement of the Wisconsin Division of Energy.

For more information on identifying phantom load or "leaking electricity", see the extensive web site maintained by Alan Meier of Lawrence Berkeley National Laboratory at http://eetd.lbl.gov/EA/Standby/Measuring/AtHome.html. Included at this web site are several excellent papers on the topic and data on expected standby electricity usage for various appliances.

For additional information, contact James Cavallo, Ph.D., Principal, at 630 971-2016 or send e-mail to cavallo@Kouba-Cavallo.com.

This page was last updated on September 7, 2001.