NEW YORKERS have often been told that they use less energy than most Americans, partly because they live in the most densely populated city in the country.
And that’s true, up to a point.
Sure, New Yorkers have the benefit of an extensive mass-transit system, which means lower auto emissions, but the city’s residential buildings are less energy-efficient than those in many other places in the country, particularly in eco-friendly states like California and Vermont.
“The main reason that New Yorkers use much less electricity is that our apartments are so much smaller” than homes in other cities, said Rohit Aggarwala, the director of the Long-Term Planning and Sustainability Office, part of the Mayor’s Office of Operations.
In fact, most big New York buildings, both commercial and residential, are wasting thousands of dollars a year on energy, the city says. Energy use by buildings accounts for almost 80 percent of the city’s greenhouse gas emissions, and residential buildings for about a third of that. These gases are released in creating the energy used to heat, cool and light the buildings, as well as to run myriad household appliances and gadgets.
Mayor Michael R. Bloomberg has created a blueprint, called PlaNYC, to control future development in the city, with a goal of reducing total greenhouse gas emissions in 2030 by 30 percent, compared with 2005 levels.
While some reductions can be accomplished by toughening the requirements for new construction, about 85 percent of the buildings that will exist in the city in 2030 are already standing.
And those buildings need to go on an energy diet.
There are a number of relatively inexpensive things that residential buildings could do that would immediately lower their energy costs and that would reduce their “carbon footprints,” the emissions these buildings are responsible for, Mr. Aggarwala said.
The easiest, and cheapest, is to install energy-efficient light bulbs in all common areas. More expensive plans — the costs of which can often be offset by loans and grants from New York State — include replacing old inefficient boilers with more efficient modern ones and installing solar panels on the roof.
Ashok Gupta, a senior energy economist and the director of the air and energy program at the Natural Resources Defense Council, a nonprofit environmental group in New York, said many buildings start with the least expensive measures with the biggest immediate payoff — buying fluorescent bulbs for about $4 each, for example, or thermostatic radiator valves for about $90 each.
But that is where a lot of buildings stop, and Mr. Gupta said he would like to see them reach a bit further, to measures whose costs could be recouped in two to five years. The next step, for example, might be installing motion sensors that would dim the lights by 50 percent when the hallways and stairwells were not in use.
In a 60,000-square-foot building with 40 apartments, hiring an electrician to install motion sensors might cost $11,000, according to estimates produced by Optimal Energy Inc., a consulting company in Bristol, Vt., that has done regional energy-efficiency studies for New York State and Con Edison. The building could save that much in lower electricity bills over two years, assuming that it was already using fluorescent bulbs, and the sensors alone would reduce its carbon dioxide emissions by about 40 metric tons per year, the company said.
That would be the equivalent of driving a car that gets 25 miles per gallon for 110,250 miles, according to Dr. Stuart Gaffin, an associate research scientist at the Center for Climate Systems Research at Columbia University.
As you would expect, it would take longer to recoup the costs of the more expensive measures.
Optimal Energy estimates, for example, that it would cost about $20,000 to weatherize that 60,000-square-foot apartment building, which could be paid for by five years of lower heating bills. Weatherizing would include sealing gaps around windows, exterior doors, and interior pipes and wiring.
Some residential buildings might also consider installing solar panels on the roof, to provide a nonpolluting source of electricity to light the hallways and run the elevators. Experts recommend doing this only after more glaring energy inefficiencies have been addressed, because in a large apartment house, solar panels are not going to produce enough energy to replace Con Edison.
Solar requires patience. It could take up to 15 years to break even on $19,000 spent on solar panels, and that is after subsidies and tax breaks offered by the state and federal governments. Mayor Bloomberg has proposed an additional subsidy for installing solar panels on buildings in New York City.
Mr. Gupta of the Natural Resources Defense Council contends that environmentalists often sell themselves short by focusing too much on payback periods. “Nobody asks what the payback period is for a marble lobby,” he said. But if a lot of large commercial and residential buildings installed solar panels, he said, that could go a long way toward reducing the city’s overall impact on global warming.
“From a societal perspective, the benefits are huge,” Mr. Gupta said.
As it stands, very few apartment buildings in New York have taken the first step and hired energy consultants. The first step most consultants suggest is to switch to fluorescent bulbs (a cheap fix), and then to solve the heating problems (to keep residents from being uncomfortable).
The Towers Cooperative, an eight-building complex with 111 apartments in Jackson Heights, Queens, last year hired Power Concepts, an energy auditor in Manhattan.
Once the audit was done, Bobbi Turner, the building’s manager, sat down with the board. They decided to start with the fixes that their in-house maintenance staff could do — for example, installing fluorescent bulbs as the old incandescents burned out. Ms. Turner said the electricity bills for the common areas were 7 percent lower last year than in 2005.
For now, Ms. Turner and the board have decided to forgo many costlier measures that were recommended, including installing separate boilers for hot water and heat to cut down on the fuel the co-op uses in the warm weather when residents need hot water but not heat.
It would have cost $86,000 to do this in all eight buildings, with a payback period of five and a half years.
But the buildings’ staff did implement other suggested improvements to the heating system, which included installing thermostatic radiator valves in all apartments.
“Our job is to make sure that we are doing things as efficiently as possible,” Ms. Turner said.
The co-op did not have a maintenance increase this year, and Ms. Turner attributes this largely to the cost savings from the efficiency measures that have been implemented so far.
Other buildings have needed to take more extensive measures to solve more complicated problems.
At 395 Riverside Drive, a 15-story co-op at the corner of 112th Street, the apartments on the west side of the building were often cold because of wintertime blasts of wind off the Hudson River. If the heat was turned up to offset the cold, apartments on the east side of the building got too hot.
The board at 395 Riverside Drive ordered an energy audit from the Association for Energy Affordability, based in Manhattan, which recommended installing additional heat sensors and upgrading the computer that regulated the heat.
These changes were made last fall, at a cost of almost $8,000. The building paid $8,500 less on fuel bills, a decrease of nearly 16 percent, from December 2006 to April 2007, despite a spike in heating oil prices, according to the building’s management company.
And the residents were more comfortable, said Dr. Eric Linden, a periodontist who is a former vice president of the co-op board.
The building also replaced the bulbs in the hallways with fluorescents, although, as at the co-op in Queens, the in-house staff replaced them gradually.
Dr. Linden credits these changes with keeping a lid on maintenance. The monthly fees, which range from $500 to $2,200, depending on the size of the apartment, rose 3 percent this spring.
“But we might have had to raise them 4 to 6 percent if the energy costs had gotten completely out of control,” Dr. Linden said.
Remarkably, the age of a building seems to have no correlation with how energy efficient or inefficient it is. Some of New York City’s most efficient are old brick-and-mortar buildings “that just have amazingly good maintenance staff,” said Michael Colgrove, a senior project manager at New York State Energy Research Authority, whose goal is to make multifamily buildings more efficient.
On the flip side, Mr. Colgrove said, owners in condominiums built 5 or 10 years ago should not be complacent. “Almost all new construction in this city can easily improve their energy efficiency by 20 percent,” he said.
Daniel M. Krainin, a lawyer who is the president of a Brooklyn co-op, had an energy audit done for his building, a converted brownstone with eight apartments in Park Slope.
F. L. Andrew Padian, the director of multifamily services at Steven Winter Associates, an architecture and engineering firm in Norwalk, Conn., that performed the audit, recommended five measures. So far, the co-op has acted on only one, installing a mixing valve on the boiler for $550. Mr. Krainin said that this cut the building’s oil bill by more than $400 in the last year.
Sometimes, Mr. Padian said, cutting fuel use is simply a matter of recalibrating some controls. “When I can walk in with a screwdriver and cut energy bills by 40 percent, people are really happy,” he said. “In other buildings, the old boiler is responsible for 85 percent of the energy waste.”
The four other measures that he recommended for the building would cost about $30,000 in all: replacing the old boiler with an efficient unit, replacing the old beat-up windows with new double-paned windows, insulating the roof and installing motion sensors on the lights in the basement.
“Thirty thousand dollars would be a lot of money for a co-op our size,” Mr. Krainin said.
After reading the audit report, residents voiced their reservations until they learned that the co-op could finance the work with a below-market loan subsidized by the state.
“Now everyone is sold on the idea that if we can do it without increasing the maintenance fees, then it makes sense,” Mr. Krainin said. “But I think we might have had more objections if we’d gotten to the point that it would cost people money in the form of higher maintenance fees or a surcharge.”
That may be the sentiment of many co-op and condo boards now, but energy-efficiency experts say that attitudes are changing fast.
Jonathan F. P. Rose, a New York developer who specializes in energy-efficient construction, said the public is much more aware of environmental issues like global warming than it was a few years ago.
Developers are racing to build new condominiums that can be marketed as “green.” And Mr. Rose said that older condos and co-ops could distinguish themselves with “energy smart building” certificates if they successfully completed the new state energy-efficiency program and cut their energy use by 20 percent.
“This isn’t a fad,” Mr. Rose said. “I think this is a cultural transition. In the future, I think there will be such a preference for green buildings that those buildings will have an edge.”