There is some experimental evidence that electromagnetic fields can exert physical effects upon the brain and can give rise to a sense of presence, unsettling emotions and hallucinatory episodes. (Michael Persinger is a key researcher in this field.) However, the type of EM fields involved are described as ‘weak and complex’, and are usually not to be found within the average household. (They are not the type of fields that can be detected with standard EM field detectors, commonly sold as so-called ‘ghost-hunting’ kits.)
Recent experiments have raised further questions regarding the role of EM fields in paranormal experiences, suggesting that the observer’s brain may predispose or protect him or her from any effects, and also showing that prior belief in the paranormal is a far greater factor in the likelihood of ‘paranormal’ experiences than the presence of EM fields.