Perhaps this east facing/west facing this has some cultural strings attached. In some Asian countries, people will choose a house which gets "morning sun" (east) rather than the "evening sun" (west). When I asked why, I was told that while morning sun is conducive to health, evening sun is harsh. Which is the same reason traditional Chinese folks will "bake" their babies in morning sun (not evening) to rid them of jaundice.
Just a guess...
PS. my altar faces west, by the way, because the layout of my room only allows for it to be placed that way.
PPS. good to be able to read and post again. thanks retro!