Maybe it would be a viable DIY troubleshooting to turn off fuses one by one and check if the LEDs stopped flickering, until the culprit is found (assuming a reasonably modern fuse box where you can just pull a switch on/off, not the old ones with ceramic fuses). That is, in case the problem is the washing machine disturbing LEDs in the living room, you would find out this way. If something connected to the same fuse is causing it or if the LEDs are just bad... well that's another story.

It's not clear to me why things on other circuits would cause this. I don't have anything in my house that uses more than 1-2A, and all the breakers are 20A max btw. Residential service is usually 100-200A.

The flickering lights don't have anything except the lights on that circuit/breaker.

matthewsnyder‭ Anything based on coils will produce voltage/current spikes whenever energized or de-energized: both the expected "EMF" used to drive whatever the coil is driving, as well as a "back-EMF" which is a current going in the opposite direction and may damage or interfere with other electrical equipment. This gives both conducted (over wires) and radiated (over air) electromagnetic emissions. The usual generators of such unwanted emissions would be DC motors like in the mentioned washing machine. Other forms of emissions are also possible like for example the intentional emissions from a wi/fi router. All of this is why electronic products need to conform to certain electrical compatibility standards before getting put on market. Now if you bought some cheap electronics from China or the like, it might not conform to such mandatory standards.

matthewsnyder‭ Although it may of course simply be a problem with the LEDs themselves, but if you experience the same problem on multiple places then maybe that's less likely.