This study examines the concept of ‘future-proofing’ the energy design of housing developments so as to achieve low-levels of energy consumption and carbon emissions over their lifecycle. This refers particularly to the selection of fabric energy efficiency measures and on-site low- or zero-carbon technologies (microgeneration or local energy networks) at an early design stage. The research adopts a multiple case study method with data gathered from two ‘best-practice’ housing developments in the UK and Sweden; namely, North West Cambridge (Cambridgeshire) and Välle Broar (Växjö). The research explores the future-proofed approaches used in the two cases in relation to a pre-established conceptual framework, which involves two aspects; namely; adopting lifecycle thinking and accommodating risks and uncertainties. The cross-case analysis reveals that there is widespread experimentation, which demonstrates that future-proofing is still in its infancy. Drivers for future-proofing mostly prompt strategies to accommodate risks and uncertainties in the UK; whereas in Sweden they lead to the adoption of lifecycle thinking. This is due to unique context-specific governance and institutional factors at both national (country) and local (case study) levels. The chapter concludes with the need to transfer knowledge to mainstream housing construction and inform policy-making in relation to long-term performance over a project’s full lifecycle.