What a "Benchmarking" Energy Audit Entails: The ABCs of EUIs and EERs
Jan. 22, 2013 — The purpose of the energy audit and its associated energy efficiency report (EER) is to identify ways to improve a building's energy efficiency, from system upgrades to operational and maintenance measures.
The year a building has to file its EER corresponds to the last digit of its block number. Buildings with block numbers ending with 3, such as your co-op or condo, will have to file their EER by the end of 2013 (the first year of filing for Local Law 87/09). Buildings with block numbers ending with 4 will have to file their EER by the end of 2014, and so on, until 2022, for buildings with block numbers ending in 2. Buildings can begin the audit and "retro-commissioning"of your building's systems up to four years before their filing deadline, in order to allow enough time and capital reserve accumulation to complete the entire process.
The audit entails a review of the property's energy bills to analyze natural gas, fuel oil and electricity use from a one- to three-year period. Much of this information can be gathered from the utilities data submitted to the city under the new benchmarking law, Local Law 84/09. In addition to looking at the utility use within the building as a whole, the review includes individual billing records for a minimum of 10 percent of all apartments, including at least one of each apartment type.
EUI A-OK
The utilities data determine the building's Energy Utilization Index (EUI), which is compared to the EUIs of similar buildings. An energy model can then be developed for the building, and based on the EUI, performance targets established — for example, increasing energy efficiency by 20 percent over the next three years.
The energy audit itself is a visual survey of the following base-building systems: exterior envelope (façades and roofs); heating, ventilation, and cooling systems; electrical and lighting; elevators; fans, motors, and pumps; and any other components that affect energy use. The audit also covers common areas, including lobbies, hallways, stairwells, basements, storage, recreational rooms, gyms, etc. In addition, the audit team will perform a limited inspection of roughly 10 percent of the apartment interiors, looking at energy-related items such as radiators, fan coil units, air conditioners, PTAC (packaged terminal air conditioner) units, vents and lighting and plumbing fixtures.
The audit includes non-destructive tests, such as infrared scans (to detect heat loss and water infiltration), domestic water pressure and temperature readings, air pressure measurements, and ventilation flow rates. To supplement visual observations, the audit firm may request investigative probes to better determine the underlying construction and conditions of areas not easily visible or accessible, such as a structural roof deck or a plumbing chase.
Talking It Out
To get a better understanding of the building's energy usage, it is helpful for the audit firm to interview building management, maintenance staff and residents. While the analysis of the building's utilities bills yields an overall view of energy consumption, discussions with those who live in and/or work for the building can provide more detailed information and insight into patterns of energy use, such as apartments/floors that are too hot or cold, drafty spaces, banging radiators, leaks, lack of hot water, peak usage times, and actions that waste energy, such as keeping doors and windows opened, leaving lights on, letting water run, etc.
After completing the audit, the audit team will present the condo or co-op board with a report that includes a prioritized list of recommendations for improving energy efficiency. A future article will discuss what types of typically necessary improvements you can expect.
Stephen Varone & Peter Varsalona are principals at Rand Engineering & Architecture.
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