Very interesting thread. Here is another along the same lines. This thread gets very technical but, the point is that there is not really anyway to solve the Radio Frequency Interference problem. The more pumps, furnace blowers, washing machines, etc, equipped with variable speed or frequency drives, the worse the problem becomes. I remember seeing a report years ago about the effects of RFI from florescent lighting causing high stress levels and other physiological problems for humans. Variable Speed or Variable Frequency Drives put out a lot more RFI than florescent lighting.