Many jurisdictions around the world have deregulated utilities and opened retail markets to competition. However, inertial decision making can diminish consumer benefits of retail competition. Using household-level data from the Texas residential electricity market, we document evidence of consumer inertia. We estimate an econometric model of retail choice to measure two sources of inertia: (1) search frictions/inattention, and (2) a brand advantage that consumers afford the incumbent. We find that households rarely search for alternative retailers, and when they do search, households attach a brand advantage to the incumbent. Counterfactual experiments show that low-cost information interventions can notably increase consumer surplus.