We use causal forests to evaluate the heterogeneous treatment effects (TEs) of repeated behavioral nudges towards household energy conservation. The average response is a monthly electricity reduction of 9 kilowatt-hours (kWh), but the full distribution of responses ranges from -30 to +10 kWh. Selective targeting of treatment using the forest raises social net benefits by 12-120 percent, depending on the year and welfare function. Pre-treatment consumption and home value are the strongest predictors of treatment effect. We find suggestive evidence of a “boomerang effect”: households with lower consumption than similar neighbors are the ones with positive TE estimates.
Keywords: machine learning, program evaluation, targeting, energy efficiency.
JEL Codes: C53; Q40; D90