55 Water Street

One of Manhattan’s Most Iconic Buildings is Guided to Huge Energy Savings With an On-site Energy Manager.

Built in 1972, 55 Water Street is the largest office building in Manhattan. This Class A commercial building, with 3.2M square feet of rentable space, is well equipped and well operated. It is also one of the country’s largest buildings with a “U.S. Green Building Council” LEED Gold Certification.

Its ownership and management teams are passionate about pursuing sustainability initiatives to reduce the building’s carbon footprint and environmental impact.

In 2021, New Water Street Corp. was approved for a cost-share with NYSERDA to hire an on-site energy manager (OsEM). Building management was looking forward to working with on-site expert who could help with sustainability initiatives and work with the building’s operations team.

Phase-One Discoveries

Steam accounted for 45% of the building’s energy use. Therefore, the energy manager’s first priority was a full steam audit. Steam leaks were quickly identified and corrected. Additional suggestions were made to improve pressure control and insulation, which provided immediate benefits. More nuanced measures, such as eliminating separate heating and cooling systems in favor of heat pumps, were investigated.

An interesting feature of the site was its on-site ice storage plant. Ice made at night (when demand for electricity was lowest and less expensive) was used for space cooling during the day (when demand for electricity was high and costly).

However, the energy manager made a recommendation to improve on-site thermal storage by using the ice storage plant to supplement heating as well. The ability to use ice year-round, for both heating and cooling, would dramatically reduce the building’s reliance on steam.

Less Steam, More Electricity

Further measures that either introduced electricity, or made its use more efficient included:

• phasing out antiquated pneumatic control systems in favor of digital controls
• upgrading induction units for more efficient space heating and cooling
• upgrading lighting and lighting controls
• installing a water source heat pump for domestic hot water. This single improvement reduced yearly steam use by 8,000 MMBTU.

Exceeding Savings Targets

Prior to hiring the OsEM, Water Street Corp developed an anticipated target of 2% yearly savings for steam and 2% for electricity. After the OsEM, the installed measures mentioned above resulted in a combined 15% reduction in the building’s total energy use, which translated into a whopping 733% energy savings compared to the target.