A new study found that tenants in green buildings experience increased productivity and fewer sick days.

The research also found that that green buildings have lower vacancy rates and higher rents than non-green counterparts.

The study, conducted by the University of San Diego and commercial real estate broker CB Richard Ellis Group, found that tenants in green buildings such as the Behnisch Architekten-designed Unilever offices in Hamburg above are more productive based on two measures: the average number of tenant sick days and a productivity change.

Another report out in the past week concluded that constructing new green buildings or retrofitting existing structures with energy efficient air conditioning, solar panels and the like will support 7.9 million U.S. jobs and pump $554 billion into the American economy over the next four years.