Software as a service (SaaS) featuring software using drone, physics and building automation system (BAS) data for use in estimating energy savings and return on investment (ROI) in energy efficient buildings; software as a service (SaaS) featuring software using drone and building automation system (BAS) data for use in identifying utility and tax rebates in the field of energy efficiency for buildings; software as a service (SaaS) featuring software using artificial intelligence (AI) and physics-based modeling for use in forecasting capital expenditures in the field of energy efficiency for buildings.