Loud buzzing noise - could it be an electric shower?

[Notcontent]

A few months ago I started noticing a loud buzzing noise that's coming from my neighbours' bathroom, which adjoins my bathroom. It's not a constant noise - just at certain times.

They did say something about having some issue with their boiler and having work done. So could it be an electric shower making that noise? And if so, should a properly installed one be so noisy?

Could it be their extractor fan? Only on when they use the shower and for a set period after the shower has been switched off? Probably more likely than the shower instead. Or could you be mistaking the sound of the water from the shower with an electrical buzz?

Thanks. I guess it could be an extractor fan... It's definitely not just the sound of water. Also, there was no buzzing noise before...

We have a shower with a pump, so on while showering, and that can be quite noisy...