Calculating how your electric bill will change after you bring home your electric vehicle is not easy in California where we have tiered electrical rates. However, I have done an analysis of the true added cost to charge an EV in the SF Bay Area on PG&E. This analysis is based on actual SmartMeter data from two different homes with different usage profiles. Of course, your situation may be significantly different than these two cases, especially if you live in the East Bay where the AC demand is much higher than western Santa Clara County. All EV charging is assumed to take place during the Off-Peak hours of 11pm-7am. The first home is a ~1,700sf 2BR 2BA single level detached townhouse in Cupertino. A retired couple lives there. This is what I consider to be a small home and their average electric usage is about 425kWh/month with only December and January over 500kWh. Choosing the best rate plan, Schedule EV, would result in an increase of about $60 per month to the electric bill at the townhouse. This comes to approximately 6 cents per mile. Staying on the same rate plan that most people use, E-1, would result in a bill increase of more than $120 per month, doubling the incremental cost of EV charging. The second case is a single family home in Los Altos with 5BR 4.5BA ~4,800sf in two stories. A family of 4 lives there including two elementary school children and one parent works from home most of the time. The average usage is about 700kWh/month for most of the year, with Nov-Jan over 800kWh and peaking at just over 1,000kWh in December. You can see that the average monthly bill without an EV is MUCH larger for the larger home. This is primarily due to the tiered rate system that penalizes high usage. The larger house is already paying over $160/mo for electricity, so adding EV charging and using a non-tiered rate adds less than $25/mo to the bill. That's only 2.5 cents per mile! The details of the Townhouse analysis can be found in a PDF here. That PDF contains the actual usage and the projected usage with EV charging calculated on E-1, E-6, E-9A, EV month by month. The single family analysis can be found in a PDF here. The spreadsheet that I used to do these calculations is here. It uses SmartMeter data downloaded from PG&E to do all the calculations. Rates in the Excel workbook are from the Tariffs effective 5/1/2014.