I recently moved to a house that has a heat pump. My plan is to install a NEMA 14-50 outlet in the garage for charging. (I plan to get a Model S this spring). I just noticed that when the heat pump starts, the lights in the house dim a bit (for perhaps a quarter of a second), indicating a voltage sag. This is probably not abnormal due to high inrush current on the heat pump compressor. I suppose this will probably also happen in the summer when the compressor comes on for A/C. The heat pump is on its own circuit at the main panel, suggesting that the voltage sag is on the power company side. This is not surprising - I am out in the country, so our house is served by its own power company transformer. The voltage sag could be in the transformer and/or the (underground) wiring between the transformer and the house. Here is my question: on this forum I have seen some discussions about the MS charging system automatically backing off charging current when it detects a voltage drop. Is it likely that the voltage sags caused by the compressor start up will cause the Model S to drop its charging current, leading to very long charging times? (If so, I suppose I could tell the power company I want this fixed, but I think they would want me to pay for it - $$$$). What do you think?