We talk often about how energy efficient New York is on a per capita basis but in the New York Times, the director of Long-Term Planning and Sustainability admits" The main reason that New Yorkers use much less electricity is that our apartments are so much smaller" than homes in other cities. Most of the buildings are still energy hogs, and emit 80% of the City's greenhouse gases.
Now Mayor Bloomberg has introduced a plan to reduce emissions by 30% by 2030. However 85% of the buildings that will exist then are already standing and need to be retrofitted.
Some things are cheap (fluorescent bulbs) and others take longer for a payback, but Ashok Gupta of the National Resources Defense Council makes a very good point that environmentalists (and TreeHugger) sell themselves short by focusing on payback periods. "Nobody asks what the payback period is for a marble lobby." Full illustration below fold and article at ::New York Times