Abstract
I study the heterogeneous returns to energy-saving technologies across locations and property types in the United Kingdom. Using administrative data from Energy Performance Certificates, the National Energy Efficiency Data framework, and the ECO programme, I document substantial variation in the returns to energy efficiency investments. I develop a spatial general equilibrium model with liquidity constraints and externalities to evaluate optimal subsidy design, finding that spatially targeted programmes yield a 3.7% welfare improvement relative to uniform allocation.