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Reduce Airflow through Elevator Vents to Cut Energy Bills
For decades, tall building facility managers have maintained open vents at the top of their properties' elevator shafts to comply with fire codes. Unfortunately, the vents allow treated air to escape; and in winter the escaping air creates a pressure that pulls cold air into the buildings.
Changes in firefighting techniques and building construction now allow building managers to reduce the vent openings, or close them altogether. These steps reduce energy loss, improve comfort and often improve buildings' air balance.
The March 2015 report, Spending Through the Roof, prepared by the U.S. Green Building Council for the New York State Energy Research and Development Authority, indicates that open elevator shaft vents can cost tall buildings over $20,000 per year--and can be addressed inexpensively. The study was written after changes were made to the New York City building code in 2014.
The New York Times quotes an authority who said that the typical 15-story building could reduce its energy bills by $3,000 to $6,500 annually by sealing its elevator shaft vents.
Spending Through the Roof lists two retrofit solutions, one simple and one more complex:
1. Cover two-thirds of each vent with annealed glass and leave the rest open.
2. Install motorized louvers that will open when code requires it. Such systems cost $5,000 to $15,000, but have a payback period of one to five years.
Regarding option 2, Massachusetts elevator code (248 CMR) regulates the venting of elevator hoistways. According to architect A. Vernon Woodworth of AKF Engineering Services, this code allows for closed vents, as long as they can be opened by:
a) an approved automatic thermostat designed to open at a temperature of not more than 90 degrees.
b) a building fire alarm system, and
c) in the event of a power failure.
The Spend Through the Roof authors recommend that building owners hire consultants to advise them on design and code compliance.
My contact at American Aldes suggests that hoteliers contact the elevator manufacturer, too. He agreed that substantial energy savings are possible, and believes that the project might change building air flow patterns. A proper analysis ahead of time would help hotels avoid unanticipated consequences.
I encourage you to read Spend Through the Roof, and determine whether it makes sense to retrofit your facility's elevator shaft vents.
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