Keep hearing a hum in house - any ideas

[ifonly4]

I've noticed over the last couple of weeks, I keep hearing a hum - in last 18 hours I've heard it three times when I'm in lounge). Sounds like it's either coming from our bedroom corner (above lounge) or from next door.

Any ideas?

Tinitus?

Neighbour's fan

My electric toothbrush makes a hum when it's charging. Is it something electrical that's plugged in?

Is it the Hum?

en.wikipedia.org/wiki/The_Hum

Wasps or bees?

It'll be a fan somewhere.

A fan or a phone on vibrate.

Radio alarm clock switched on by mistake and very low?? Took us a week to work that one out!!

Fridge working harder than usual die to high temps at the mo

Thanks for your replies. I've heard it since at 10pm, 11pm, 5am and 10am. Only lasts 5-10 seconds - but the one at 5am definitely coming from neighbours side and was louder as I was upstairs - I'd almost say it's in his roof, which is strange as he doesn't use that (we're in a dormer bungalow).

There's a lady who sometimes comes to help him, so I might see if I can catch her - just wondering if his boiler is in the roof. He's an elderly chap, so don't want to worry him. He gets up around 5.30am, so it'd make sense the boiler coming on then as he keeps house very warm.

Could they be alarms for taking medication or something, making a phone vibrate? Those are exact hours, so would make sense if they were timers.

Happy serial killer? Check under the bed.

Sorry - I'll cut it out.