Power outages and unreliable electricity supply have potentially high economic costs; however, existing empirical evidence on the magnitude of these costs or the value of electricity reliability is limited. In this paper, I provide some of the first revealed-preference estimates of household willingness to pay to avoid power outages (also referred to as residential value of lost load) using a defensive expenditures approach. Combining this approach with proprietary, store-transaction level sales data for all generators sold at every retail store of a major national home improvement retailer from 2012-2020, I find that a household is willing to pay $1.57/kWh of avoided outage. Given this estimate, I perform various back-of-the-envelope evaluations of potential utility investments in improved reliability, the outage-related costs of hurricanes, and total household willingness to pay to avoid average annual outages, which I calculate to be greater than $1.2 billion per year.