How a 145,476 Sq. Ft. Multifamily Building Was Assessed for a 62% Potential Energy Reduction

Project Overview

A 145,476 sq. ft., 19-story multifamily building with 136 residential units in New York City needed a detailed assessment of its existing energy performance before prioritizing future improvements.

Built in 1941, the building presented opportunities to improve the performance of its existing systems. The client needed to understand where energy was being used, evaluate potential Energy Conservation Measures (ECMs), and determine which improvements could deliver the greatest potential impact.

The assessment also needed to support the client's efforts toward compliance with New York City's Local Laws 87 and 97, while providing a reliable basis for future capital investment decisions.

The goal was not simply to identify individual upgrades. It was to understand the building's overall performance and develop a practical basis for prioritizing future energy improvements.

The Challenge

The project required NY Engineers to:

• Establish a reliable baseline of the building's existing energy performance.
• Evaluate potential energy conservation measures across the building.
• Compare individual improvements and broader upgrade strategies.
• Quantify projected energy savings and potential greenhouse gas reductions.
• Determine which measures could deliver the greatest potential impact.
• Provide a data-backed basis for future capital improvement planning.

The recommendations needed to be supported by a calibrated energy model so that potential improvements could be evaluated against the building's actual operating conditions rather than assumptions.

Energy Modelling Approach

Establishing a Reliable Building Performance Baseline

Before evaluating potential upgrades, the building's existing energy performance needed to be established.

An ASHRAE Level II Energy Audit was conducted alongside a calibrated energy model to represent the building's existing operating conditions. This created a reliable baseline for evaluating potential Energy Conservation Measures against the building's actual performance.

Evaluating the Building as an Integrated System

The assessment evaluated the building's existing energy performance across its major systems and improvement opportunities.

Rather than treating each potential upgrade independently, the analysis considered how different measures could contribute to the building's overall energy performance. This provided a broader view of where improvements could deliver meaningful potential savings.

Testing Potential Improvements Through Energy Modeling

With the baseline established, multiple Energy Conservation Measure (ECM) scenarios were evaluated using the calibrated energy model.

The analysis examined the potential impact of packaged terminal air conditioner-to-packaged terminal heat pump upgrades, thermostatic radiator valve controls, domestic hot water heat pump upgrades, building envelope improvements, and broader electrification strategies.

This provided a consistent basis for comparing potential improvements before implementation.

Prioritizing the Highest-Impact Improvements

The analysis showed that different measures offered different levels of potential energy savings.

The electrification package demonstrated the greatest overall potential, with a 62% potential reduction in total energy use.

Individual measures also showed meaningful potential, including PTAC-to-PTHP upgrades, thermostatic radiator valve controls, domestic hot water heat pump upgrades, and building envelope improvements. These findings provided a basis for prioritizing future improvements according to their projected impact.

Project Outcomes

The project provided a technical foundation for evaluating future energy improvements. The ASHRAE Level II energy audit and calibrated energy model were completed within the required two-week schedule, with NYSERDA approval achieved after one revision.

The analysis quantified the potential impact of individual energy conservation measures and identified a broader electrification strategy with significant potential for reducing overall energy consumption.

Rather than evaluating upgrades in isolation, the client received a data-backed basis for comparing improvement strategies and prioritizing future investments.