Energy Efficiency in the Homelab

At what point should you either downsize your homelab (I know, blasphemy) or consider upgrading your hardware to something more energy efficient?

Power consumption is the insidious, hidden cost of a homelab.

Thoughts/reflections/summary from the post below:

  • Electricity costs quickly add up. A back of the envelope calculation shows that just 200W of continuous power consumption can easily be $15/mo in additional power costs, and that’s without even including the additional cost of air conditioning.
  • Good rule of thumb for estimating power costs: 24/7 usage ~= $1 per watt per year
  • I use a couple of “smart outlets” like the TP-Link HS110 in my homelab to monitor energy usage:

    These can typically be had for under $30/each. As an added bonus, I use mine as a “poor man’s IPMI” in the case of a kernel panic which will allow me to yank power from my server to WOL later. If you buy a different one, be sure to check the current rating first. The nice thing about the TP-Link, even though it can be a little more expensive than other smart plugs is that it is rated for a full 15 amps, whereas the cheaper ones are not.
  • Use more efficient endpoint devices. If you’re running a Plex server, use HEVC/x265 decoding capable client devices so that your server never has to transcode. Transcoding uses a lot of energy, produces a lot of heat, and sucks up precious bandwidth. And on top of all of this, transcoding produces an inherently inferior picture.
  • If you already have a running homelab, you don’t have to guess what your usage/workload looks like. Your current usage should give you a good idea of what you need to run efficiently. In my case, I went the opposite direction of many of the responses. I replaced my dozen or so Raspberry Pis and NUCs and instead consolidated them into one virtualization server. Those small, cheap plastic boxes have instead been replaced with VMs. They run faster (with comparable power usage) and the server itself has plenty of room to run (as determined by CPU utilization and IOwait).
    -If you’re running old, big hardware (like most used server racks are going to be), are you really using all that power? (Honestly, saying an old server is powerful is probably a bit of a stretch compared to modern architecture). Do you really need a 24 core Xeon to host a Wordpress site? Consider downsizing that server to a Raspberry Pi or NUC.
  • The biggest advantage of virtualization is that most servers were sitting at minimal CPU usage 99% of the time. Use that to your advantage and consolidate to a virtualization server.

Here’s the Reddit post that sparked this review:

Have anything else to add? Want to review your current setup? Chime in below!