[changadera]

My neighbour has a heat pump and it's kind of annoying when running because the 180hz hum is audible in most of the rooms in my house. This in the UK and our houses are detached, but fairly closely spaced.

[switch007]

A constant hum from a neighbour's heating unit would drive me crazy. We have lots of terraced and very-close-together housing in the UK...

Low frequency noise can travel quite far (and through mass), so not even distance helps that much

[dv_dt]

I wonder if there is some isolation dampers that could be added to the mounts (sounds fancy, but think rubber or silicon grommets).

[timbit42]

Most heat pumps mounts I've seen have rubber grommets but older heat pumps will make audible noise as they wear out.