improving construction toward reaching sustainability goals (e.g., by improving insulation, or using HVAC systems with a higher efficiency) will have a marginal impact on the overall construction cost, and that benefits due to such excess costs are well worth the original investment. However, this needs to be substantiated so for each clause of the Israeli Standard 5281 (Buildings with reduced environmental impact—“green buildings”), the excess cost of green over conventional building, was matched against the benefits accrued.