There are many different types of energy audits you can perform in your home.  I wanted to determine the cost of unused electronics, known as phantom energy use.  This includes both the cost of devices turned off, but still using power and those that are on (or in standby mode) despite not being used.

I focused my efforts on things that I could change with little or no impact to my life.  An example is the TV I have in my guest room.  Leaving it unplugged, versus plugged in but off, wouldn’t affect my life since that TV is only used when visitors are here.  Plugging it in before they arrive would take minimal effort.

The Device for Testing

For my testing, I used the P3 International Kill a Watt, model P4400.  This energy monitor allows you to measure the kWh (and more) of any devices connected to it.  By using a power strip, you can measure multiple devices.  Since it cost about $21, I was hoping to be able to identify at least that much (per year) in wasted energy to recover the cost.

Items to Test

Guest Room TV

As described above, leaving this TV plugged in seems wasteful, since it is rarely used.  Using the Kill a Watt, I learned that it was using 0.720 kWh per day, which costs me $16.29 per year!  My first test identified a waste nearly as large as the cost of the testing device.

Networking Equipment

Though I wouldn’t want to leave my networking equipment powered off all the time, I could easily unplug it at night.  I could also put this equipment on a timer so that it was on during waking hours and off while I’m asleep.  The devices, from left to right, top to bottom are a NAS Server, cable modem, Vonage, 5 post switch, and router.  Powering off the cable modem and Vonage box would kill my home phone, but Vonage automatically reroutes calls to my cell phone in such cases, so that would be fine.  This equipment uses 0.370 kWh in a 10 hour period which is the amount of time I can turn it off on a normal night, or with a timer.  That energy costs me $8.36 per year.

Family Computer

To save energy, I had been placing my computer in standby mode each night.  By testing the energy use in standby and regular operating modes I was able to determine the following: standby only reduces consumption by 37%.  That’s better than nothing, but I could reduce consumption by 100% by completely powering down.  10 hours of standby at night uses 0.896 kwH costing $20.27, even more than the guest room TV!  So I’ll obviously turn the computer off instead of putting it into standby at night.  I also calculated that every hour of active use per day costs $3.26 per year and every standby hour per day costs $2.02 per year.  So every extra hour during the day that I can get my computer into standby mode instead of active mode will save me another $1.24 per year.

Printers

These fall into a similar category as networking equipment.  I generally want them on duing the day and don’t want to have to go turn them on before I print.  But I could easily live with turning them off overnight.  In 10 hours, these printers (plus the attached 5-port network switch) use 0.133 kWh, costing $3.01 per year.

SubWoofer

Last but not least is the subwoofer for my surround sound system.  By only plugging it in while I’m watching TV, I could virtually eliminate its operating cost.  In the 22 hours a day I’m not watching TV (2 hours a day is a high estimate for my TV habits) this subwoofer uses 0.160 kWh, which cost $3.63 per year.

Results

All told, the wasted energy in the listed devices accounted for 14.35% of my most recent bill.  Eliminating this waste will save me $51.57 per year.  This may seem like a lot of upfront work to save $4.30 a month, but hardly took any time at all.  You could adjust your use without measuring the actual savings, but I prefered to know how much my efforts would save.  Then I could determine if that savings was worth the change.  Since these changes are the ones which will have little or no impact on my life, it was an easy decision to make.  The Kill a Watt will have paid for itself in less than 5 months and I can use the remaining savings to purchase timers, should I choose to automate the nightly power off process.