Using Timers and Motion Switches to Save Power


Here are some examples of using Motion Switches and Timers of various types to make sure things are turned off when not in use.


Motion Switches

A motion switch can be used to replace an ordinary wall switch.  Once installed, it will turn on the light (or other device) only when it senses that a person is in the area. 


The ones we use have a three position switch with: an "off" position, in which the light is always off, an "auto" position in which the motion detector controls whether the light is off or on, and an "on" position in which the light is always on.  They also have a control that sets how long the light stays on after no motion is detected. 


These are quick to install, and, in our experience, work reliably.  We currently have one in the bedroom walk in closet, and one in the kitchen pantry -- these are lights we were having trouble remembering to turn off.  We plan to add more of them.

An added bonus is that if you have your hands full of stuff, you don't have to figure out how to flip the light switch with your elbow.


Be sure to turn off the circuit breaker for the wall switch before installing the new switch.


See Doug's story below for other uses.



There are a several types of timers that


Wall Switch Replacement Type Timer

These windup timers replace a standard wall switch.  To use them, you turn the timer dial to the amount of time you want.  The light or fan or whatever is on the circuit controlled by the switch/timer stays on until the timer winds down, and then shuts off.


Some homes have wall outlets that are controlled by wall switches.  These switches can be replaced by a timer switch, which will then control anything plugged into the wall outlet.  See below how Doug uses this to keep the kids from leaving stuff like TVs on.







24 Hour Timers

For things that you want to be on for a bit every day, the 24 hour dial timers with the


I have a lot of battery operated tools, and its tempting to leave the chargers plugged in with a battery in them so that when I want to use the tool, the battery will be charged up.  But, the phantom load from all of those chargers adds up -- in my case it was 19 watts.   This is about 170 KWH a year and 300 lbs of CO2 emissions just to keep the battery tools ready to go.  The payback period on the timer price is less than half a year.


I now use one of the 24 hour plug in timers to control the chargers for all of the battery operated tools in the shop.  I plug all the chargers into a power strip, and plug the power strip into the timer.  The timer is set to turn on for a bit each day -- this keeps the batteries for the tools charged up and ready to use.  When I'm not actively working on a project, I just unplug the timer -- this way all the rechargeable tool chargers are not using any power at all.


Click on pictures to enlarge

All of the chargers plugged into power strip
just behind the chargers.  Power strip is
then plugged into the timer on the wall
just behind the left most charger.

With all the chargers at idle after fully
charging their batteries, the KillAWatt
reads a 22 watt phantom load.



Energy Saving Idea For Those Folks With Kids!

Here is a report from Doug on using timers and motion switches:

Energy Saving Idea For Those Folks With Kids!

I had an idea a while back to save on energy consumption. Anyone who has kids can attest, they leave lights on. The more I ask that they be turned off, the more frustrated I get. So I put timers on the kid's room lights. I also put motion sensing switches on the bathroom where I would most frequently find the light left on. Solved many of the times I would be running around turning lights off when the kids were nowhere to be found.

Then came the television. I would come into the play room, and the TV, xBox, VCR/DVD player..... All left on. So I put them on a power strip as suggested by many, and had the kids start turning that off. But as usual that would stay on much more often than it would be turned off. SO I thought, why not employ the same idea of the timer to the power strip? So off to Home Depot I went and got a bathroom fan timer and a plastic electric box. When I got home, I nailed the box to the entertainment center. I unplugged the power strip, and wired the switch in the power strip power cord. Bingo! Now when the kids want to watch or play games, they have to give the timer a twist. The TV and games become accessible for up to 60 minutes before having to re-set the timer.

I know it's a simple fix, but it seemingly has eliminated me having to remind the kids to turn the TV off!


Gary May 1, 2010