After receiving a $225 electric bill for the month of December (on top of the $250 gas bill), I was curious to see what my various pieces of gear in the house cost/month. I ordered a clamp amp meter and started sleuthing. I first pulled out the old Pepco bill and after some simple math determined that the cost/KWh is ~$0.14. Anecdotally, this is about 10-20% higher than all states in our region. Continuing on, extending the formula KWh = (Amperage*Voltage)/1000, it’s easy to see that for a device that pulls 1A and runs 24×7, the cost is $0.37/day or ~$11/month. From there, it’s simply a matter of using the amp meter to measure the amperage and multiply by $11 to get the ~cost per month for that device. My workstation with 1 HDD and 1 SSD pull around 0.3A for a monthly cost of $3.30. My Linux server with 6 spinning disks pulls around 0.6A or roughly $6.60/month. with the screens turned off pull anywhere from 0.3 to 0.6 amps or around $3.30-6.60 per month. I also measured my entertainment system that is composed of 9 difference devices, i.e. cable box, xbox, receiver, and the 50″ plasma. It’s “standby” pull was 0.3A/$3.30 per month. Active watching TV etc, the pull was closer to 3.3A! I’m going to have to do the math but there may be a solid return on investment if I junk the old plasma and purchase a newer 10x more efficient LED.
