Heating, cooling, and insulation: A simple assessment of a facility’s heating and cooling systems and their energy-efficiency ratings is merely the tip of the iceberg. A thorough assessment also must examine how many exposures a facility has to the outer environment — windows, truck doors, doors for personnel to travel in and out of — as well as what kinds of materials were used for a facility’s walls (and how thick they are), what types of roofing shingles have been used (and what their R factor is), and how many days per year each system is in use.