<p>Electric vehicles (EVs) can reduce greenhouse gas emissions, but widespread adoption is held back by higher upfront and—in some cases—lifetime ownership costs. Here, for a representative EV across the contiguous USA, we estimate the impact of different charging strategies on owners’ electricity bills and greenhouse gas emissions for charging and other household uses over the vehicle’s lifetime. We account for local climate, regional differences in vehicle use and projected grid decarbonization during the EV’s lifetime. Compared with uncontrolled charging, optimizing charging and using EV batteries to optimally shift electricity purchases for other household loads, a strategy referred to as vehicle-to-home (V2H), could reduce emissions from non-EV household loads by more than EV charging increases emissions in 69% of US counties, covering 62% of the population. V2H could cut costs by US$3,800 (5th–95th percentile range US$2,400–US$5,600) or 61% (37%–91%) and life-cycle emissions by 38 t CO₂-equivalent (24 t CO₂-e–57 t CO₂e) or 89% (50%–150%).</p>