Three Men and a Boiler

Credit Ira Meister, president of Matthew Adam Properties, with a “brilliant” idea. That’s what Jacqueline Stein, the secretary at York River House, the 225-unit Lenox Hill building that he manages, calls his method to save dollars.

As part of a renovation to switch from No. 6 oil to dual fuel boilers for heating, the York River House also wanted to install new, high-efficiency hot water heaters and storage tanks – a common project for a green-thinking building. But the cooperative’s approach was anything but typical. “Ira figured out that we should really see who was gone over the summer,” says Stein. “I’d love to take credit for it. It’s just brilliant.”

Knowing how many residents of the 225-unit Lenox Hill building were away during the summer months enabled the board and managing agent to know what size of hot water units were truly needed, says Meister. “You don’t have to buy too big or too small,” he says.

The approach to get a summer head count was equally innovative. A survey might seem intrusive and could be ignored, says Stein. Instead, Meister worked with the buildings’ doormen to do an informal count. “They know who has kids, whose kids are in camp, who is at the Hamptons every week,” Meister says. Stein, who estimates that she’s in the Hamptons for about 60 percent of the summer, joked: “The doormen know that at Apartment X, the three kids are at sleepaway camp and they know it because they’re the ones who picked up the duffle bags on June 28.” Going to the doormen for information allowed the board to get details on summer occupancy without “turning it into a project within a project,” says Stein.

The end result determined that only about 45 percent of the building is occupied during summer months. The old hot water system worked the way many do in the city: coils within the heating boilers are used to heat water that is destined for residential use. The problem with that type of system is that it requires the boilers to be fired year-round, a costly and wasteful practice that creates more hot water than is actually needed. At York River House, however, the new system includes two new high-efficiency hot water heaters that are separate from the boiler system.

“They are downsizing to exactly what they need,” says project engineer Ralph Germain, vice president with Robert F. Germain. He notes that the soon-to-be installed dual-fuel system will also have a coil system that can be used to provide hot water, but most of the year, the building will rely on the independent hot water heaters. “During the summertime, they most probably will only be using one unit,” says Germain.

The cost of the water heater system, a Lochinvar model CFN1802PM, is $150,000, and it can provide 6,500 gallons per hour of hot water with the storage tanks that were used.

The new system will reduce the fuel consumption by half in the summertime, when only hot water is produced, not heat. “Generally, when the boilers are making heat, we will use the coils in the boilers for the hot water due to the boilers being hot already because they need to make steam for heat,” says Michael Bendjouya, owner of Controlled Combustion, the contractor on the job. “We expect $20,000 savings annually,” and a return on investment in about eight years.

“There are additional benefits besides efficiency,” Bendjouya adds. “If the boilers break down, the water heaters can run independently, so the building always has hot water. The boilers can ‘rest’ over the summer, extending their useful life. If one of the boilers breaks down in the coldest weather, the hot water load can be removed and the lone boiler can make heat in the coldest weather.” In the buildings that convert from oil to gas, about 10 to 15 percent of the time, Bendjouya says he also installs a separate hot water heater.

“A typical building without air conditioning has the boilers off from mid-May to mid-October,” says Bendjouya, leading to almost five months of downtime.

“When the boilers are used for air conditioning, the boilers are only off from mid-May to mid-June and from mid-September to mid-October,” he notes, a much shorter time.

The process does not make as much sense for buildings that use steam as part of their HVAC systems to create air conditioning. (While it seems counterintuitive, hot steam can power an AC system by heating a liquid with a refrigerant, causing the refrigerant to evaporate.) But those types of systems have a long payback for a dedicated hot water heater because that equipment generates the most savings when the boilers are off.

The Energy Detective Weighs In

Tom Sahagian, Habitat’s “Energy Detective” columnist, offers his opinion on the York River House innovation.

Many buildings should consider emulating York River House, but since every building is different, you’ve got to make the right calculations to determine if a separate water heater is right for you.

Domestic hot water (DHW) systems are notoriously difficult to size. York River House’s approach is an interesting one, but remember, it’s a guesstimate at best – and if you travel down this route, take into account that building demographics can change.

A more accurate way to size the DHW system would be to temporarily meter the consumption, determine the peak load, and select equipment accordingly. You are likely to end up with an even smaller and less expensive system.

Note that it could actually be more cost-effective to size the system for the entire load and run it year-round, except in the case of buildings like York River House that have to switch to oil during the coldest days.