It is easy to laugh at the concept of an EMF friendly home, and to ascribe all interest in such to nut-jobs. Keep in mind, however that there is a certain amount of reality here, with some number of people demonstrably sensitive to stuff that you or I don't notice.
A very interesting set of anecdotes can be found if you search for posts by Karl Riley, both here and on the Mike Holt board.
1) We say 'EMF', but since we are dealing with the 60Hz wiring surrounding us in homes, we really should not think in terms of electro-magnetic radiation (energy radiating through space, where energy is constantly flowing between a changing electric field and a changing magnetic field), but rather we should be thinking in terms of near field approximations, where currents in wires are creating magnetic fields, or charged wires are creating electric fields.
2) What I take from Karl's anecdotes is that the vast bulk of situations where people could 'sense' or be adversely affected by wiring could be ascribed to _magnetic_ fields. These magnetic fields are caused by unbalanced current flows, meaning current flowing in a conductor that is not matched by current flowing in the opposite direction in an immediately adjacent conductor. The vast bulk of these situations are actual code violations, eg. bootleg neutrals, unintentional parallel neutrals, etc. In other words, the bulk of the situations where people 'feel' the wiring were situations where there is a well defined code violation that can be fixed. What this means is that careful adherence to code will get you most (if not all) the way to an EMF friendly home.
3) Code does permit some situations that can cause significant unbalanced current flow; eliminating this becomes a design issue. The big one that I can think of is shared underground metallic water piping acting as a parallel neutral. For an 'EMF friendly' home, I would suggest plastic underground piping to eliminate this shared neutral path.
4) In the US, conventional 120V wiring has one 'hot' and one 'grounded' conductor; this will produce a net _electric_ field between the cable and the surroundings. If someone is sensitive to electric fields (as opposed to magnetic fields), then running a MWBC with both supply legs present in the same cable would seem to reduce this. Using wiring methods surrounded by grounded metal would also likely reduce this. (Again note: we are talking about electric and magnetic fields separately here, and it seems that people are sensitive to _magnetic_ fields if anything.)
5) My personal _hunch_ is that the low intensity electric and magnetic fields produced by home wiring do no direct health damage, but that some people are just sensitive enough to them to be annoyed by them, without being able to clearly identify the problem and so be able to decide to ignore it. This continual annoyance is what then triggers health damage. I personally experience this sort of thing where an extremely quiet but unidentified sound will keep me awake, while I try to figure out what the hell is making the noise and wishing it would go away. Most people would just sleep through the sound, but it grabs my attention, sets my teeth on edge, and ruins me the next day. Perhaps these people are particularly sensitive to audible 60 Hz hum, and the magnetic fields make things vibrate, and the vibrations are what annoy them. Perhaps these people really do barely detect the changing magnetic field itself. I don't know.
6) There are lots of BS artists out there selling things related to EMF.
-Jon
