When I first sarted using this monitor, I lived in a house.  The monitor worked great without any interfearance.  It picked up every little sound that my son would make.  We have since relocated to an apartment and it still picks up my sons movements pretty good, but it also has some light static interfearance.  It is not enough to keep me awake at night, but it is quite noticeable at higher volumes.  I even had to use it without the power adapter for the monitor for a couple weeks after the move (we lost the adapter).  Batteries lasted for 1 week, using it for 10-11 hours every night!!!