Building owners and managers in NYC continue to prepare for the first Local Law 97 compliance submission in 2025. While Local Law 97 impacts properties throughout NYC, complying can be especially challenging for those with dated heating systems. Buildings with one-pipe steam heating systems, for example, often face energy efficiency challenges due to the combination of an inefficient building envelope; oversized radiators; and ineffective system operations. So, how do you address these concerns without replacing the entire system? How do you achieve occupant comfort, energy savings and compliance at the same time? In this blog, we take a look at how one-pipe steam systems work and how they can be optimized for both savings and compliance.
First, some background on one-pipe steam systems:
As the name suggests, one-pipe steam heating systems use a single pipe to perform the dual functions of supplying steam to the radiators and returning condensate (the water formed when steam cools and condenses) back to the boiler. Steam travels efficiently when there are no interruptions. In a typical system, the boiler generates steam and distributes it to horizontal steam piping, called steam mains, installed in the basement. Vertical steam piping, called risers, are connected to the mains, allowing steam to travel through various floors and leading to the terminal units, such as radiators and converters. Steam travels through this system and condenses as it rejects heat, thereby heating the spaces. As the steam condenses into condensate, it creates a vacuum in the pipe. And since the system uses the same pipe (hence the name) to transfer steam and condensate, the vacuum creates major hurdles for the steam to travel through the pipes. Air vents are installed on steam mains, risers and radiators to remove the air from the system and enable optimal operation of the system.
Over a period of time, this system experiences major issues and inefficiencies. Typical areas of concern include:
- Failed vents on mains and risers
- The inability to efficiently remove air from the distribution
- Missing piping insulation, which results in heat loss
These issues can result in inefficient distribution of heating within the building. The most common method for building operators to provide heat is to crank up the steam pressure, making parts of the building overheated. So, how do we address the myriad of one-pipe steam issues?
The Solution
At Bright Power, we target system improvements in three key areas of heating – generation, distribution and controls. We start by addressing the distribution which involves ‘balancing’ the system. The goal is to make steam travel as efficiently as possible through the optimal combination of measures:
- Replacing the vents on the mains, risers and often time radiators with right sized vents. Sizing vents requires a detailed study and should be performed by experienced professionals only.
- Next, all exposed steam piping should be insulated. This significantly reduces the heat lost through pipes and also reduces water hammering (another issue resulting from inefficient distribution).
- The next step in the process addresses generation and controls. We recommend installing indoor temperature feedback sensors in at least 25% of the apartments, plus upgrading the boiler controls to operate based on both indoor temperature and outdoor conditions. This will ensure that the boilers are operating optimally and distributing heat evenly throughout the building, ultimately reducing energy consumption and carbon emissions.
Achieving Local Law 97 Compliance
For many eligible properties, implementing prescriptive energy conservation measures (PECMs) is the first step in meeting Local Law 97 requirements, and they must be completed by the end of 2024. These solutions are part of the (13) mandatory PECMs. Whether your building’s compliance pathway is through PECM implementation or the Standard pathway, improving an inefficient one-pipe steam system should be one of the first steps a property takes.
Long Term Benefits
Addressing one-pipe steam issues is more than a stepping stone to achieve LL97 compliance; it can also present significant savings opportunities for your property. Our newest case study shows how addressing one-pipe steam in a Queens co-op helped the property achieve more than 30% savings. Check out the case study here.
Find Out More
For specific questions about your property’s heating system or to complete a Local Law 97 pathway assessment, contact our team of experts.