So How Much Power Does a Home ESXi Server Use After All?

I started wondering how much power my home ESXi host was really using, but I didn’t have any tool to measure the actual energy usage. So this week I took the plunge and bought a small energy monitor to take a few measurements. The results were pretty interesting.

The Hardware

  • Asus H81I-Plus motherboard
  • Intel Pentium G3220 CPU with stock cooler
  • 2 x 8 GB Kingston 1,333 MHz DDR3 Non-ECC RAM
  • 2 x Western Digital Red 2 TB drives
  • Corsair CX430 Power Supply

As you can see, nothing fancy, but enough to run a few VMs at the same time and do some decent testing (the CPU performs especially well for the price).

The Power Consumption

These are the results of the measurements I took over two days of usage. They don’t mean to be scientific: every value represent the average of the power consumption I could observe during the tests.

  • Booting the server: 40W
  • Idle, no VMs running: 30W
  • Booting 4 VMs: 40-45W
  • Idle, 4 VMs running: 30W
  • Plex streaming one movie: 40-42W at the beginning, back to 30-32W afterwards
  • Downloading one series of a TV show to a client machine: 36-37W
  • Uploading one series of a TV show to Plex: 34-38W
  • Uploading a 4GB ISO to the datastore: 35-37W
  • Creating a VM: 32W
  • Installing Windows 10 in a VM: about 35W, peak of 50W
  • 4 VMs idle + 1 Windows VM idle: 35-45W

So as you can see, the power consumption is very, very reasonable. I have also left the energy monitor plugged in for two days to measure the energy consumption for my typical usage. The total energy usage has been of 1.5 kWh over two days, so 0.75 kWh per day. At my energy price (about £0.15 per kWh) this amounts to about £0.11 per day. A pretty reasonable price if you ask me, which shows that running your own server at home doesn’t necessarily have to be a huge expense.


  1. I just built a server with almost identical specifications (although I have only 1TB of storage instead of 4TB).
    Have you thought about using FreeBSD? Jails are brilliant and use less resources than virtual machines.

    • Yes, I am currently running FreeBSD (actually, FreeNAS) on another HP Microserver machine I had lying around. I am using jails for ownCloud and Plex currently, and I love the concept. I am just not sure I feel ready going FreeBSD-only just now though :)

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