Party Walls

New York City: the city that never sleeps—and where buildings account for approximately two-thirds of greenhouse gas emissions.

In 2019, New York City Council passed Local Law 97 (LL97) to hold building owners responsible for carbon emissions. The goal is to reduce over time, eventually reducing emissions 80% by 2050. As it stands, the law applies to most buildings over 25,000 square feet, which is roughly 50,000 residential and commercial properties across the five boroughs.

One pathway to decarbonize New York City’s buildings is using the Passive House standard: a high-performance building standard that significantly reduces whole building energy consumption by up to 60-70% while providing superior comfort and indoor air quality. When coupled with renewable energy systems, Passive House makes net zero energy buildings more feasible. (more…)

Most people who have lived or worked in a steam-heated building are familiar with the typical occurrences of uneven heat (underheating/overheating), banging pipes, and having to open windows all winter long. Not only are occupants uncomfortable, but the heating bills are high as well.

Balancing these systems is a huge opportunity for energy savings. It is important to point out that the root of the issue is in the distribution system, and it’s that distribution system that needs to be fixed. The steam traps are the weakest link, and when they fail, residents lose the ability to control the amount of heat delivered. This in turn makes the space uncomfortable and results in the necessity to open windows and waste fuel.

The steam traps are supposed to be replaced building-wide every three years to catch broken traps, but due to the expense and logistics of such a task, this is rarely done.

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A common strategy to provide ventilation in multifamily buildings is to design a central roof-top air handler that distributes outdoor air to each unit. The energy cost for this system, which commonly uses natural gas for heating for either a gas furnace unit or hot water from a central boiler is paid for by the building owner. However, there is another option – VRF[1]. With the unprecedented rise of VRF technology in the last decade combined with regulations such as New York City’s Local Law 97 of 2019[2] (carbon emission penalty), the industry is taking a giant leap towards building electrification. There are always questions and concerns raised against building electrification ranging from initial cost to operating cost to reliability of the VRF technology. From the owner’s perspective, the biggest question is usually surrounding the operating cost of an electric system compared to a natural gas system for heating, but the cost of ownership must consider multiple energy metrics. I was curious to understand the impact on various building energy profile metrics associated with a Dedicated Outdoor Air System (DOAS) using the conventional gas fuel source vs. the latest VRF heat pump technology using electricity in a multifamily building. The findings of this investigation challenge the deep-rooted notion that electricity, being more expensive than natural gas per BTU, will always cost more to operate.

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