Ok, your guess is as good as mine, and you'll be only going on the vague babblings I give you but I'm wondering if you can figure out something I've been trying to figure out for... oh, a year or two?
Here's my vague babblings...
The neighbour above me (I'm pretty sure) has a thing that they use that makes a noise that annoys me.
Ok. We'll start there.
I first heard this noise a summer or two ago and so assumed it was an air conditioning unit, but I never saw the "box sticking out of the window" thing so then I figured not.
Well, I've heard it again as of this last week or so, and I still don't see the box in window thing so I'm trying to figure out what else it might be. Perhaps a fan? But it seems to have a consistent Hummmmmmmmm rather than what a rotating fan might sound like. But I could be wrong. I've thought it might be the dishwasher, but that usually has a limited run time and also usually has water sounds, and well, unless they eat a lot, they're probably not running the dishwasher every night. Right?
I know I don't have fans out right now but the apartment above me is probably warmer, so maybe they need it?
I checked to see if it's the building's laundry or drier but nope. I'm typing this at 8pm at night and I hear the hummmmmmm.
I don't know much about air conditioner sounds. Never had one, didn't grow up around them, so have no idea what I'd be listening for. A fan I suppose makes sense, but I generally only hear the noise in the evenings (as far as I've noticed?)
I wish I could explain the noise to give you better guesses but it's like a ... uh... a low hummmmmm. That's all I know. It's consistent and constant.
Fan? Or, air... thing of some kind? What else might it be? I'm not about to knock on their door and be like hi, can I please just come inside to look around and oh ok, just pretend I was never here, bye! But part of me would like to!!!!
Edited to Update: Ok, I feel like after I finished writing this the noise stopped, and now it's come back on again so I really really have no good guesses!