We compile a dataset comprising seven million residential real estate transactions in the United Kingdom to examine homeowner valuation of dwelling sustainability. Homeowners pay a premium for more energy-efficient dwellings. Exploitation of the spatial, temporal, tenurial, and vintage heterogeneity in the premium shows that homeowners price the energy efficiency of their dwellings following economic principles. We propose a simple valuation model to recover the discount rates used by homeowners, which provide direct measures for rates used to discount investments in sustainable development and climate change mitigation. The rates demonstrate that homeowners accept lower returns for greener dwellings, indicating non-pecuniary incentives.