The author has found a valid bug in the firmware that results from a combination of settings. You would have to test to see if it results in power savings. I would have thought power use was a function of the amount of traffic and clients.

(Author here.) The estimated savings is roughly 24 Euro/year assuming the AP is completely idle (which it mostly is at night). So, that's the savings from just disabling one of the radios. Europe is currently experiencing an affordable energy shortage. So, everyone is encouraged to cut energy usage. One AP doesn't make much difference, but this change is something almost every AP — residential and business — could make to cut waste. It should probably be a first-time setup question: do you want to save energy by disabling the 5 GHz radio between 23:00 and 07:00?

A bit heavy on the snark, but I have to agree… of all the hundreds things I could think to do to micro-optimize power usage around the house, disabling the 5ghz band on my router at night doesn’t even remotely make the list.

Edit: I mean, the time keeping the computer turned on to write this post wiped out how many decades of savings in disabling a Wi-Fi band?

I spent far too long trying to wrap my head around that. Are they making popcorn with their Wi-Fi router or something?

You'd probably lose more money from the efficiency loss of AC to DC conversion than you'd get back doing something so arbitrary