The paper demonstrates the use of Multiple Decision Diagrams (MDDs) in consideration of building energy retrofit options. Candidate retrofit alternatives including associated key performance indicators (KPIs) (e.g. cost, energy, embodied carbon) can be compiled into MDDs where various performance implications can be effectively illustrated and KPI trade-offs explored. We argue MDDs are flexible supporting a wide range of computations around the decision process. Significantly, we show KPIs can also be used as constraints in the search for satisfactory retrofit configurations and conclude that the MDD approach complements existing methods of optimising building energy retrofit options by providing a reduced initial search space.