|Intel System||System On||Deep Sleep||Shutdown|
|Sparkle PSU (power strip)||35.5 W||2.1 W||1.5 W|
|Sparkle PSU w/ Smart AV||36.2 W||2.4 W||1.8 W|
|Sonamu PSU only (power strip)||37.1 W||4.6 W||5.5 W|
|Sonamu w/Power Module||38.1 W||4.6 W||5.5 W|
|AMD System||System On||Sleep||Hibernate||Shutdown|
|Sparkle PSU (power strip)||38.6 W||37.2 W||0.6 W||0.5 W|
|Sparkle PSU w/ Smart AV||39.3 W||38.0 W||1.0 W||0.9 W|
|Sonamu PSU only (power strip)||39.1 W||38.8 W||3.2 W||3.2 W|
|Sonamu w/Power Module||40.2 W||38.8 W||3.2 W||3.2 W|
Our measurements reveal several things. Compared to a generic power strip, the Smart AV consumes about 0.3 W extra when the master device is in a low-power state, in order to monitor power use. When the master device is on, power consumption increases to about 0.7 W in order to activate the slave power outlets.
Moneual's Sonamu case consumes about 1.0 W more to turn on the auxiliary power outlet. However, if the motherboard doesn't support a system-off sleep mode, Sonamu's power module does not turn off auxiliary power. That is what happened with our older AMD system.
|Home PC||Power Used (Idle)||Power Used (Active)|
|Canon MP560||0.9 W||1.1 W|
|Samsung 23" LED LCD (PX2370)||0.2 W||25.7 W|
|Uverse Router||13.0 W||13.0 W|
|Logitech 2.1 S220||1.0 W||3.0 W|
|Total Idle Power||15.1 W||42.8 W|
In California, the current average cost of energy is $0.13 per kilowatt-hour. Assuming 21 hours per day of idle time, we can save about $0.04 per day, or $15.20 per year by shutting off our peripheral devices. Keep in mind that most of that comes from shutting down the U-verse router, which you may or may not want to do, depending on the other devices that rely on it. Today, most LCDs, printers, and speakers have very low idle power consumption. Completely cutting power doesn't substantially change the amount of power used, at least not in the home office.
Calculating savings is a bit tricky. If you were to use your home computer three hours each day, the cost of using Belkin's Smart AV with our Sandy Bridge-based system would be $7.01 per year (that's including power used even when the computer is off). With the Sonamu, the cost would rise to $11.02 because of the higher power use when the system is turned off. That's a result of its inefficient PSU that uses more power when it's in a low-power state. Fortunately, The cost of using the Sonamu can be brought down to $5.48/year, but only if you use its on/off power switch to completely kill power to the system. Compare this to a generic power strip, which would end up costing you $6.61 for the entire year.