|PC Power Supply|
I converted an old HP desktop PC into a home file server using the NAS4FREE free software a while ago. The server works well and I have made some modifications to it over time. The cost savings in electricity surprised me.
First, I replaced the motherboard with a low power mini-ITX motherboard. The original motherboard had a power hungry old AMD processor and I did not need all that computing power. This decreased the power consumption from 150 watts to 75 watts, for a monthly saving of $6.21 or $75 per year (local cost of a kilowatt hour is $0.115). I also sold the old motherboard and memory on Ebay so my net cost was about $25, for a 3 month payback.
Second, I replaced the HP power supply with a modern energy efficiency Bronze-certified power supply (Corsair CX430). This further dropped the power consumption to 35 watts, saving $3.31 a month or $39.75 a year. The power supply was on sale for $29.99 so the payback is about 9 months. For those geeks among us, it also corrected the power factor from around 1.3 to 1.
Two things I noted:
- You can save money by getting more energy efficient devices, like this server that is on 24 hours a day. Clearly, home PC's as sold by the manufacturers are not very energy efficient.
- Even a small power draw like 35 watts (a couple of CFL bulbs) adds up over time if the device is always on - $40 a year.