The Net-to-Gross Equation

Every high-rise carries a hidden number few developers ever ask about: how much of its floor area actually does anything - and what the rest is quietly costing in energy, every single year, for the life of the building.Backed by a dataset of 34 buildings, 20 expert interviews, and eight projects tracked across five design stages, this book proves what practitioners have long suspected but never measured: spatial efficiency isn’t a leasing metric with a side effect on sustainability - it’s one of the most powerful, controllable levers on a building’s lifetime energy performance. In hot arid, high-density markets specifically, each percentage point of Net-to-Gross ratio lost is associated with a 10.43 kWh/m²/year increase in energy intensity - 46% steeper than the equivalent effect in temperate-climate buildings (R² = 0.887).The book doesn’t stop at the finding. It delivers the ASEF-S framework - a regionally calibrated, three-dimensional assessment tool with an Energy Consequence Calculator that lets architects and developers see the energy cost of a spatial decision at concept stage, before it’s locked in for forty years.Written for architects defending design decisions in review, developers underwriting feasibility, sustainability consultants bridging regional and international certification systems, and researchers extending the methodology - this is the first book to put a number on what inefficient space actually costs, and a tool to close the gap while it’s still cheap to change.