A reliable roadmap starts with the building and its energy baseline. Depending on the project, this includes the envelope, windows, heating, cooling, hot water, ventilation and the use of renewable energy.
For each proposed stage it should be possible to identify the component or system being changed, the preparatory work and the expected improvement. The order and interfaces are equally important. Later facade insulation, for example, may affect earlier planning of windows, cables or connections.
Owners should keep technical descriptions, plans, photographs, consumption data, existing energy documents and legal documents in separate but linked records. This makes clear which statement is based on a measurement, a design or an assumption.