Question Screen goes black when I turn on my bathroom lights

Nov 27, 2019
7
0
10
Now this is an error description I'd never tought I'd need to give:
I live in a relatively small but modern apartement and recently build a new PC as my current Laptop is getting too slow for my work. I now noticed that if I turn on the bathroom lights in my apartement (or turn them off after having them on for a little while) my PC monitor turns black for a short amount of time (maybe 1/2 or 1/4 of a second).
The monitor itself seems to stay on during that time (at least the backlight stays on) and the image seems to continue where it was - so it doesn't restart.

What could that be and is it bad for the PC?
My bathroom lights seem to be connected to the air conditioning system - the bathroom air conditioning system turns on after having the lights on for a few minutes - does that have something to do with it?