Multifamily and office buildings are responsible for 90% of water consumption among large buildings in New York City. Additionally, buildings with automatic water meters subject to the Benchmarking Law (Local Law 84 of 2009) must report water consumption every year, and results revealed that multifamily buildings consume eight times more water than office buildings. Therefore, water conservation efforts can have the greatest effect if they are focused on the multifamily housing sector.
- According to building benchmarking data, the average water use intensity (WUI) for multifamily buildings in New York is 50 gal/ft 2 . However, some properties exceed 300 gal/ft 2 .
- Office buildings, which follow multifamily buildings in terms of consumption, typically have a WUI of less than 20 gal/ft 2 and properties with higher WUI reach up to 140 gal/ft 2 .
While environmental sustainability is the main driver of water conservation in New York, energy savings are also achieved in the process. Water conservation has reduced pumping expenses and domestic hot water systems also experience a reduced heating load. Consider that domestic hot water represents the fifth largest energy consumption in New York, representing 11% of energy consumption in large buildings in general and up to 19% in multifamily buildings. The potential for emissions reductions is also significant, since most water heating in New York is done with natural gas or fuel oil.
Water conservation measures can achieve synergy with point-of-use water heaters, which eliminates standby losses from storage heaters as well as piping losses when hot water must travel a long distance between a heater and a electrical device.
Importance of reliable water consumption data
Measurement is the first step to gaining control over any variable, and water consumption in a city is no exception. To improve its billing capabilities, the New York Department of Environmental Protection is installing automatic meter reading (AMR) devices. These units are equipped with a low-power radio device and communicate with a network of receivers installed throughout the city, with the collaboration of the Department of IT and Telecommunications. DEP can become much more efficient with AMR units since its employees no longer need to visit properties to take manual readings.
Another advantage of AMR devices is that they integrate with a web application that can be accessed by homeowners to better manage their water consumption. They can visualize how water consumption is distributed by day, week, month and year. Additionally, the Benchmarking Law covers water use in individual buildings above 50,000 ft 2 as well as groups of buildings above 100,000 ft 2 under the same tax lot or condominium property – valuable data on water consumption is being collected . AMR devices will be installed in more than 830,000 properties in New York at zero cost to their owners.
Improving Plumbing Fixtures in Multifamily Buildings
The U.S. Environmental Protection Agency launched its WaterSense program for bathroom fixtures, which labels products that offer proven water savings compared to conventional fixtures. Properties classified as affordable housing are also eligible for Con Edison rebates that cover 100% of the cost of some plumbing upgrades.
Showers
According to the US EPA, showering accounts for about 17% of water consumption in residential environments, representing about 40 gallons per day for the average US family and 1.2 billion gallons per year for the entire country. As a result, shower improvements have significant potential to save water.
A conventional shower built to 1992 standards uses water at a rate of 2.5 gallons per minute (gpm), and this figure may be even higher for older units. However, WaterSense-labeled shower heads use less than 2.0 gpm and also have a uniform spray pattern – research conducted by the US EPA indicates that homeowners prefer a uniform pattern over a concentrated jet of water or a spray shaped spray. ring. WaterSense showerheads have also been tested by approved third-party agencies to validate their performance.
By upgrading to WaterSense showerheads, the average U.S. family can save 2,900 gallons of water per year and more than 370 kWh of electricity on water heating. Across the country, this benefit could amount to US$2.2 billion in water bills and US$2.6 billion in energy bills.
Multifamily buildings in New York City classified as affordable housing are eligible for free shower upgrades for residential units. The Con Edison incentive program offers a rebate that covers the total cost of upgrading up to two shower heads per household as long as water consumption is less than 1.5 gpm, exceeding the requirements of the U.S. EPA's WaterSense program.
Bathrooms
Toilets are the plumbing equipment that consume the most water in residential environments, accounting for 30% of use. The federal standard is 1.6 gallons per flush, but WaterSense labels require 1.28 gallons per flush or less. The savings are even greater when replacing old toilets, which can consume up to 6 gallons per flush. In other words, a WaterSense toilet provides water savings of 20% when replacing a unit that meets federal standards and up to 80% when replacing old, inefficient units.
Faucets
WaterSense faucets use just 1.5 gpm, achieving significant savings compared to faucets built to the federal 2.2 gpm standard. If every tap in the country were upgraded to a WaterSense unit, it could save more than $1.2 billion a year on water and energy bills.
As with showers, New York multifamily buildings classified as affordable housing are eligible for free upgrades through the Con Edison incentive program. Each housing unit may receive up to four tap aerators installed free of charge, as long as the following water usage requirements are met:
- 1.5 gpm for kitchen faucets
- 1.0 gpm for bathroom faucets
Conclusion
Water conservation measures allow for direct savings through reduced water bills from the Department of Environmental Protection, and indirect savings from a reduced water heating load. Homeowners planning to upgrade their domestic hot water systems can optimize their investment by focusing on water conservation first, which can allow them to purchase new water heaters that are both smaller and more efficient. The services of a professional consultant or engineering firm are highly recommended to find the combination of upgrades that produces the greatest return on investment.
