Three of the four bills apply only to residential and commercial buildings of 50,000 square feet or more. Among other things, the GGBP creates a New York City energy conservation code and implements standards for building performance benchmarking, lighting retrofits and tenant submetering, and audit and retro-commissioning measures.

One major change in the legislation since it was introduced in 2007 is the elimination of a requirement that large building owners follow up their energy audits with mandatory retrofits. Additionally, owners may waive the audit requirement if they are Energy Star or LEED for Existing Buildings-certified.

In a statement, Rohit T. Aggarwala , director of the Mayor's Office of Long Term Planning and Sustainability, calls passage of the GGGBP "probably the most important single step among PlaNYC's 127 initiatives to reduce our greenhouse gas emissions. Reaching our 30 by 30 goal"--a 30% reduction in the city's carbon footprint by 2030--"will require progress on many fronts including renewable energy, transportation, transit-oriented planning, and open space, but addressing energy use in existing buildings is clearly the most critical issue for New York."