The linked article on Multifamily Executive Magazine is a very solid overview by Carl Seville (green builder, educator, and consultant) on green-certifying apartments. Here are a few choice paragraphs to whet your appetite:
Owners can save money on construction costs and utilities, as well as maintenance and repairs over the life of the building, while tenants benefit from lower energy and water bills, quieter units, improved comfort, cleaner air, and a healthier indoor environment. Lower utility costs, in turn, can lead to easier tenant acquisition and better retention.
Durability measures included in green building programs can reduce long-term maintenance and repair costs through improved moisture management, which also serves to improve indoor air quality. A combination of installation techniques and materials selection results in less dust, dirt, mold, and mildew within units as well as lower transmission of odors and sound between units.
Careful design and construction also avoids excessive material use and waste. Designing buildings to standard material modules reduces the number of cutoffs needed, for example, while efficient construction techniques provide structural integrity while eliminating nonessential materials, thereby reducing costs and providing more room for insulation.