During the build, it would be worth speaking with the contractor/project manager about when energy efficiency initiatives are being installed. You could ask what measures the contractor plans to take in order to ensure effective installation. If any installations are being outsourced, it is recommended to try to gather information about how to use the system in order to optimise usage. Although this is not the responsibility of the managing trustee, it could be productive to remind the contractor/project manager of the church's vision to work toward net zero carbon.