In Bronx, NY, the Amalgamated Housing Cooperative (AHC) embarked on a pioneering low carbon retrofit project at ‘The Towers,’ two 20-story buildings containing 316 affordable apartments across 425,000 square feet. Established in 1927, AHC is the oldest limited equity multifamily co-operative in the country.
The retrofit focuses on upgrading the heating and cooling infrastructure to enable simultaneous operation, diverging from the existing seasonal limitation. By introducing cutting-edge solutions including wastewater heat recovery and geothermal systems, AHC aims to harness energy from domestic water sources, thereby phasing out its reliance on cooling towers and decreasing fossil fuel consumption. This initiative not only promises enhanced thermal comfort and sustained affordability for its residents but also sets a benchmark for energy efficiency and climate resilience. The project’s success could potentially revolutionize energy management across similar multifamily complexes in New York State, demonstrating a scalable model for other buildings with similar heating and cooling system configurations– a total market estimated at 200 million square feet.
AHC’s commitment to its low-to-moderate income community underscores this ambitious venture, reinforcing its legacy and leadership in sustainable development.
Project Status
Planning
Under Construction
Monitoring & Evaluation
Project Highlights
Emissions Reductions
93%
carbon emissions reduction on an all-electric site by 2035.
Lessons Learned
This project will make clean energy from dirty water by recapturing heat from sinks, showers, and toilets.
Lessons Learned
The project’s complete building re-piping decrease the future loaded needed for the planned geothermal heat pump system improving performance and comfort.
Scale
200 million SFof multifamily building stock for potential replication across New York State.
Step 1
Step 1: Examine Current Conditions
A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.
Building System Conditions
System Failure
Equipment nearing end-of-life
New heat source potential
Comfort improvements
Indoor air quality improvefments
Facade maintenance
Resilience upgrades
Efficiency improvements
Asset Conditions
Recapitalization
Capital event cycles
Carbon emissions limits
Investor sustainability demands
Owner sustainability goals
Market Conditions
Technology improves
Policy changes
Infrastructure transitions
Fuels phase out
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The Towers are two of 13 buildings that comprise AHC’s multifamily campus located in the Bronx. Many of the systems at the property, including the piping distribution system, are beyond their useful life and in poor condition, causing leaks and requiring continual repair and maintenance. The campus currently uses a central gas-powered boiler plant to produce steam for heating, cooling, and domestic hot water.
As part of its recapitalization cycle, the property is embarking on a decarbonization journey which will include a comprehensive retrofit of the heating, cooling, and domestic hot water systems, an envelope upgrade, and onsite renewable generation in the form of geothermal and solar PV.
This project will increase thermal comfort and secure utility affordability for its low-and-moderate income residents, as well as enhance the energy efficiency and climate resilience of the property.
Step 2
Step 2: Design Resource Efficient Solutions
Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.
Existing Conditions
This diagram illustrates the building prior to the initiation of Strategic Decarbonization planning by the owners and their teams.
Click through the measures under “Building After” to understand the components of the building’s energy transition.
Sequence of Measures
2024
2026
2028
2030
Building System Affected
heating
cooling
ventilation
Learn More
Reduce Energy Load
New hydronic distribution: Replace the dual temperature hydronic system with new piping supplying both heating hot water and chilled water simultaneously to provide heating or cooling year-round improving tenant comfort. The measure includes new fan coil units with more efficient motors and designed for low temperature heating hot water to reduce the load on the buildings and facilitate heat pump technology integration.
Envelope Improvements: roof insulation, window replacement and air sealing walls
Ventilation Maintenance: balancing and sealing of ventilation system to reduce exhaust air
Controls Upgrades: Install modern control system to automate and optimize new heat pump systems
Recover Wasted Heat
Wastewater Heat Recovery: Recapture heat from wastewater using WSHPs to produce heating, cooling, and domestic hot water (DHW). Use wastewater as heat sink in cooling mode to enable removal of old cooling towers.
Full Electrification
Ground Source Heat Pumps: Drill boreholes on property land and install WSHPs to produce heating, cooling and DHW. Use boreholes as heat sink in cooling mode.
Solar PV: Install solar PV system on rooftop
Electrify Appliances: install electric dryers and cooking equipment
Step 3
Step 3: Build the Business Case
Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.
Decarbonization Costs
$33M
Capital costs of decarbonization.
Business-as-Usual Costs
$29.5M + $35k / YR
BAU cost of system replacement.
Repairs & maintenance.
Business-as-Usual Risks
N/A
LL97 fines do not apply at this property.
Decarbonization Value
$6.7M
Incentives.
Net Present Value
$1.97M
Versus -$1.36M for BAU with difference of $3.33M.
Learn More
To confirm the viability of The Towers adopting energy efficiency measures, the project team constructed several discounted cash flow financial scenarios utilizing Net Present Value (NPV) or the total cash flow of the measures taken over a period of time by assuming a discount rate for the worth of money over a period. For comparison, they constructed a baseline for forecasted equipment replacement compared to the Roadmap measures. A comparison of investment costs are as follows:
Using a 7% discount rate over 20 years, the discounted cash flows resulted in relative net present values (NPVs) of -$1.36 million for the Baseline and +$1.97 million for the planned ECMs, a difference of $3.33 million. Based on the analysis, the cost of planned ECMs is a more viable financial investment.
Notably, the costs of business-as-usual in these scenarios do not capture what New York State prescribes as the Social Cost of Carbon (SCC). The SCC is a metric used by countries, states, and other authorities having jurisdiction (AHJ) to place a cost on climate change impacts. New York State firmly defines the SCC as $125/ton of CO2 emitted. The alternative energy system for The Towers, though capital intensive, has clear economic benefits. This and many other climate change impacts such as point pollution, land degradation, human health, and others, are known as intangible decarbonization benefits.
Strategic Decarbonization Action Plan
An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.
Learn More
The measures used in our decarbonization strategy have been strategically planned based on priorities, as well as to optimize energy and carbon reduction. The approach is to reduce loads first to allow for reduced and properly sized new systems. This sequence enables implementation of the measures because it allows thermal loads to be reduced as soon as possible, before electrification of heating and cooling with the ground source heat pump (GSHP) system. Most critical to the success of the plan are the early implementation of the distribution system retrofit and installation of the wastewater energy transfer (WET) system for thermal energy recovery.
Due to the critical nature of the decarbonization work, AHC desires an aggressive implementation timeline for the measures. The work, specifically the piping and fan coil unit (FCU) replacement and WET system installation, is slated to occur 2024-2026. Then in 2026-2028 comes the critical steps of envelope improvements, submetering and control upgrades, and geothermal system installation. The geothermal measure will be a critical step for transitioning The Towers away from fossil fuels because the GSHP system will replace the steam supplied from the gas and oil fed central boiler plant for heating, cooling, and domestic hot water (DHW). This measure will allow the chiller, cooling tower, and steam piping to be fully decommissioned, thereby yielding additional operational and maintenance savings. In 2028-2030, installing the solar PV system will allow for further deep energy savings as it will enable The Towers to have a direct source of clean energy and rely less on the main electricity grid, which needs time to transition to clean energy. Lastly, in 2039-2034, electrifying the appliances will be the last component in completely transitioning The Towers away from on-site fossil fuels while also saving energy by installing high efficiency alternatives and providing health benefits to the residents by eliminating gas stoves.
A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.
Building System Conditions
Asset Conditions
Market Conditions
Learn More
Step 2
Step 2: Design Resource Efficient Solutions
Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.
Learn More
Step 3
Step 3: Build the Business Case
Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.
Decarbonization Costs
Business-as-Usual Costs
Business-as-Usual Risks
Decarbonization Value
Net Present Value
Learn More
Strategic Decarbonization Action Plan
An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.
Learn More
Project Team
Additional Resources
Tags
With so many systems poorly installed and with maintenance so often neglected, ventilation systems in previous eras were often seen as the source of problems and little else. But today, a mixture of technological advancements and the migration of products from other markets places highly efficient systems that provide exemplary air quality and comfort within reach of virtually every building.
The days of balancing indoor air quality against energy use are over, with modern systems decoupling ventilation from cooling, utilizing high performance energy recovery ventilation (ERVs), and dedicated outside air systems (DOAS) that allow for high volumes of fresh air while drastically limiting the loss of heat and humidity. Decoupling ventilation from the heating and cooling systems is a key element of the Resource Efficient Decarbonization (RED) framework and a critical phase in producing low carbon buildings with the highest quality indoor environments.
During this High Rise / Low Carbon series program developed to support the Empire Building Challenge and other NYSERDA programs, hear from critical leaders in this field as they discuss how these innovative ventilation systems are addressing critical needs across all segments of the building sector, while also providing the foundation for full electrification.
Moderator
Benjamin Rodney, Vice President, Construction, U.S. East Region, Hines
Presenters
Daniel Bersohn, Associate, BuroHappold Engineering Benjamin Rodney, Vice President, Construction, U.S. East Region, Hines
Speakers
Vinca Bonde, Sales Director, Energy Machines Grace Kolb, Mechanical Engineer, AKF Group Tony Abate, Vice President and Chief Technology Officer, AtmosAir Miguel Gaspar, Vice President/Group Leader, Loring Consulting Engineers Dr. Marwa Zaatari, ASHRAE Distinguished Lecturer, Partner at D-ZINE Partners, enVerid Systems Advisory Board Member
A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.
Building System Conditions
Asset Conditions
Market Conditions
Learn More
Step 2
Step 2: Design Resource Efficient Solutions
Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.
Learn More
Step 3
Step 3: Build the Business Case
Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.
Decarbonization Costs
Business-as-Usual Costs
Business-as-Usual Risks
Decarbonization Value
Net Present Value
Learn More
Strategic Decarbonization Action Plan
An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.
Learn More
Project Team
Additional Resources
Tags
Lessons from New York’s Empire Building Challenge
This article, published in NESEA’s BuildingEnergy magazine (Vol. 40 No. 1), addresses common “decarbonization blind spots” that impede progress and shares insights gained from the incremental methodology and integrated design process pioneered through NYSERDA’s Empire Building Challenge.
A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.
Building System Conditions
Asset Conditions
Market Conditions
Learn More
Step 2
Step 2: Design Resource Efficient Solutions
Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.
Learn More
Step 3
Step 3: Build the Business Case
Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.
Decarbonization Costs
Business-as-Usual Costs
Business-as-Usual Risks
Decarbonization Value
Net Present Value
Learn More
Strategic Decarbonization Action Plan
An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.
Learn More
Project Team
Additional Resources
Tags
Insights from Empire Building Challenge
Large commercial and residential buildings must overcome various hurdles before implementing deep retrofits or capital projects that help achieve building decarbonization. This section addresses technical barriers and questions often faced by building owners and retrofit project developers.
Decentralized Systems and Tenant Equipment
Access to Occupied Spaces.
Lease Concerns.
Regulatory Limitations of Rent Stabilized Apartments.
The building owner is required to provide free heat and hot water.
No mechanism to recover investment in new systems is necessary to achieve decarbonization.
Buildings are capital constrained.
Split Incentives (e.g. tenants pay for energy).
Facade and Windows
Work must be completed at the end of facade/window useful life; very long useful life.
Building codes.
Glazing reduction at odds with aesthetic/marketability concerns.
Difficult installing with occupied spaces.
Reduce Local Law 11 recurring cost via overcladding
Aesthetic concerns
At odds with historic preservation
Capital intensive
Lot line limitations
Technology Limitations
Need higher R-value/inch for thinner wall assembly:
Vacuum insulated panels
Aerogel panels/batts
Zero-GWP blowing agents for closed cell spray foam (nitrogen blowing agent needs to be more widely adopted)
Ventilation
Energy Recovery Ventilation (ERV)
Space constraints
System tie-in point accessibility/feasibility
Rooftop Supply Air (Reznor) Unit Alternatives
Heat pump alternatives to eliminate resistance heat
Combine with ERV
HVAC Load Reduction (HLR) Technology
Vent or capture exhaust gases
Space constraints
System tie-in point accessibility/feasibility
Central vs. Decentralized Ventilation Systems
Direct Outside Air System (DOAS)
Modular perimeter ducted air heat pumps:
Competition for leasable space
Space constraints
Ventilation Points-of-Entry
Aesthetic concerns
Lot line facades/building setbacks
Competition with leasable space
Space constraints
Heat Pump Limitations
Variable Refrigerant Flow (VRF)
Fire and life safety concerns about volume of refrigerant gas located within occupied spaces.
Regulatory risk from new refrigerant policies
PTAC and VTAC
Ducted Supply/Exhaust Air Source Heat Pumps
Domestic Hot Water
Central DHW Systems:
Limited domestic production.
Performance not confirmed by independent third parties.
More demonstration projects needed.
Decentralized DHW Systems
More open-source interconnection between devices/interoperability is needed to achieve energy distribution flexibility and capacity expansion:
Air source that has a manifold connection to interconnect with water source or refrigerant gas distribution.
Interconnectivity/simplified heat exchange between refrigerants/water/air, etc.
Other options and add-ons.
Steam Alternatives and Barriers
Below are high temperature renewable resource alternatives to district steam. These alternatives are limited and face barriers to implementation due to cost, scalability, and other factors.
Deep Bore Geothermal
Renewable Hydrogen
Carbon Capture and Sequestration
Biomethane
Electric Boilers
High-temperature thermal storage
Hight-temperature industrial heat pumps
Waste Heat Capture and Reuse
Fission
Barriers to Electrification and Utility Capacity Limitations
Building Electric Capacity Upgrades
Electric riser capacity
Switchgear expansion
New service/vault expansion/point-of-entry space constraints
Capacity competition with other electrification needs:
Space heat and cooling
DHW
Cooking
Pumps and motors
Local Network Electric Capacity Upgrades
Excess Distribution Facility Charges (EDF)
Contributions in Aid of Construction (CIAC)
Gas Utility Earnings Adjustment Mechanisms (EAM) focused on System Peak Demand Reductions
Partial Electrification concepts achieve deep decarbonization but do not necessarily achieve peak gas demand reductions (debatable)
Total Connected Loads and Peak Demand drive need for capacity upgrades
Demand reduction strategies do not obviate capacity limitations unless the utility accepts the solution as a permanent demand/load reduction strategy.
Battery Storage:
Fire danger
Space constraints
Electricity distribution limitations
Structural loads
Building Automation/BMS/Demand Response:
Cost
Integration limitations; Blackbox software
Microgrid development cost and lack of expertise
On-site Generation:
Space constraints
Gas use; Zero carbon fuels availability is non-existent
Structural loads
Pipe infrastructure
Thermal Storage
Space constrains
Structural loads
Technology limitations:
Vacuum insulated storage tanks
Phase change material (DHW, space heating)
Geothermal (ambient temperature), Deep Bore Geothermal (high temperature) or Shared Loop District Energy Systems provide cooling and heating with lower peak demand than standard electric equipment
Building pipe riser limitations; need additional riser capacity:
Building water loops are typically “top down” – cooling capacity is typically located at rooftop mechanical penthouses; cooling towers at roof. Some exceptions to this rule
Space Constraints
Drilling Difficulty:
Outdoor space constraints for geothermal wells
Difficult permitting
Mud and contaminated soil disposal
Overhead clearance constraints for drilling in basements/garages
Shared Loop/Thermal Utility Limitations:
Requires entity that may operate in public ROWs and across property lines
Utilities are limited by regulations for gas, steam or electric delivery versus shared loop media (ambient temperature water).
Only utility entities can provide very long amortization periods
Utilities are best suited to work amid crowded underground municipal ROWs.
Deep Bore Geothermal Limitations:
Requires test drilling and geological assessment
Seismic risk
Drilling equipment is very large – more akin to oil and gas development equipment
Subsurface land rights and DEC restrictions
Other Energy Efficiency/Conservation Measures with proven/attractive economics (these measures are limited by lack of capital or knowledge)
A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.
Building System Conditions
Asset Conditions
Market Conditions
Learn More
Step 2
Step 2: Design Resource Efficient Solutions
Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.
Learn More
Step 3
Step 3: Build the Business Case
Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.
Decarbonization Costs
Business-as-Usual Costs
Business-as-Usual Risks
Decarbonization Value
Net Present Value
Learn More
Strategic Decarbonization Action Plan
An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.
Learn More
Project Team
Additional Resources
Tags
These playbooks summarize retrofit strategies that maximize occupant comfort and energy savings through a transition from fuel to electricity- based heating, cooling and hot water systems.
Playbooks are organized by building system— lighting & loads, envelope, ventilation, heating & cooling, and domestic hot water– detailing common existing systems, typical issues, and recommended measures.
A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.
Building System Conditions
Asset Conditions
Market Conditions
Learn More
Step 2
Step 2: Design Resource Efficient Solutions
Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.
Learn More
Step 3
Step 3: Build the Business Case
Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.
Decarbonization Costs
Business-as-Usual Costs
Business-as-Usual Risks
Decarbonization Value
Net Present Value
Learn More
Strategic Decarbonization Action Plan
An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.
Learn More
Project Team
Additional Resources
Tags
Insights from Empire Building Challenge
It is clear today that the use of fossil fuel-fired equipment in buildings has a limited future due to technological advancements, policy changes, ESG requirements, and other externalities. As asset managers, sustainability managers, and their consultants pursue decarbonization plans, misconceptions about decarbonization arise that can delay action and progress. Below is a list of the misconceptions encountered by NYSERDA’s Empire Building Challenge team and our recommended approaches that debunk these inaccuracies.
1. Simple Payback Measures
Instead of looking for tangential ways to create value, energy efficiency and decarbonization projects repeatedly fall into the trap of using energy savings (and some may now include carbon emissions fines savings) to justify investments in energy conservation measures. Often, this linear thinking approach yields unattractive investment economics. Alternatively, conduct scenarios analyses including net present value calculations: The lowest net present cost or negative net present value (NPV) over the decarbonization period will help inform the prioritization and selection of energy conservation measures. Demonstrating the return on investment (ROI) and/or internal rate of return (IRR) on the incremental cost of action over a do-nothing baseline will help persuade real estate owners to prioritize these projects. Rather than a simple payback analysis that looks only at the decarbonization path, the analysis should focus on comparing a decarbonization path with a “business-as-usual” path. This approach helps isolate the incremental cost of decarbonization over a business-as-usual approach.
This type of analysis requires completing a Strategic Decarbonization Assessment (SDA), which is based on a Discounted Cash Flow (DCF) analysis over the decarbonization period. The SDA should include the complexities of a capital refresh, tenant improvements, and non-energy benefits. Asset investment should be in the context of a comprehensive decarbonization roadmap rather than simply reactive maintenance.
2. One-to-one Equipment Swap with Air Source Heat Pump Is the Best Electrification Option
A one-to-one equipment swap with air source heat pumps, which is typically the first full-electrification option considered, may not be a realistic decarbonization strategy – particularly for owners of large buildings facing various constraints around thermal distribution systems, roof space, tenant disruption, and energy supply. In fact, it is advantageous to determine the building’s need for heat pumps toward the end of the decarbonization road mapping process to ensure that the heat pumps can run optimally. Significantly reducing loads, recovering and reusing heat wherever possible by enabling thermal networking, and using a cascading approach to decarbonizing easy-to-electrify loads are likely advantageous steps to take before installing heat pumps. Systems should be optimized to deliver heating or cooling efficiently over the integrated sum of the year’s diverse conditions, the vast majority of which are at part-load. Efforts to reduce and shift loads can help reduce peak capacity. However, electrification of more difficult peaks may require special consideration within the building’s roadmap and taking a rational approach to resilience and accounting for evolving electric grid or thermal network supply conditions. This is the foundation of Resource Efficient Decarbonization.
3. Electrify Everything… Immediately and All at Once!
Perhaps because the electrification movement was born in mild-climate California, the cold-climate, tall-building narrative has been incomplete. Decarbonization skeptics suggest that if it doesn’t make sense to electrify everything in one simple move, then it doesn’t make sense to electrify anything. The reality is that tall buildings in cold climates like New York must overcome space constraints and distribution challenges to provide comfort at peak load conditions without straining the electric grid or requiring oversized, sticker-shock-inducing equipment capacity.
A more suitable slogan for Northeast electrification champions would be “Electrify Everything Efficiently.” Engineers should model building energy consumption data across granular temperature bins (see Figure below) and plan for electrification with “easy” loads like domestic hot water, then mild temperature loads (typically representing 80%+ of total loads), and finally for the extremes. This is the cascade approach. Until a viable solution emerges, a building owner might even keep a small gas-fired boiler and their steam radiators around as a reserve as they learn to grapple with resilient functionality at heating design conditions. Despite global average temperatures increasing, cold snaps may even become more extreme due to a collapsing winter Polar Vortex.
4. Technology Installed Today Will Be Obsolete Tomorrow
There are plenty of technology-neutral enabling steps to take prior to committing to a particular low-carbon retrofit technology. Buildings are constantly evolving and exist on a continuum unless demolition is planned. Reducing loads, enabling thermal recovery, sharing and networking, and implementing grid interactivity are all priority measures that might take place prior to electrifying heat sources. Consultants also must determine the value of inaction and the value at risk if a building owner decides to do nothing. Balancing this risk with the pace of technological innovation is a delicate analysis and is impossible to conduct without a Strategic Decarbonization Assessment. When in doubt, look to leverage existing infrastructure like using chilled water loops for heating to replace partial loads. Electrifying perimeter heating used during extreme temperatures may be a later priority or absent from the critical path on a strategic decarbonization roadmap. Look to the case studies emerging out of the Empire Building Challenge for more information on this strategy.
5. My Tenants Don’t Think This is a Priority
Consider the tangential benefits of pursuing decarbonization early. For example, more and more Class A tenants are demanding environmental action from landlords to comply with shareholder environmental, social, and corporate governance (ESG) requirements. Accelerating facade improvements may reduce the need for invasive and expensive maintenance down the line. Indoor air quality, improved comfort, and operability are emerging priorities among all tenant types.
6. Electricity Produces Emissions
Yes, but not for too much longer. States are legislating 100% carbon-free electric grids like New York did in the Climate Leadership and Community Protection Act (Climate Act). Modeling total emissions over time using declining electric grid carbon emissions coefficients across multiple decarbonization scenarios is an important task. Phasing in electrification over time and in a strategic way is the only pathway to eliminating on-site emissions.
7. It’s Too Disruptive and Expensive to Decarbonize a Building All at Once
Achieving carbon neutrality typically requires and benefits from a phased approach versus decarbonizing all at once. Incremental implementation of low-carbon retrofits across a continuum is critical to reaching building operations carbon neutrality in cold climates. Evaluate the cost-effectiveness of phasing and maintaining technology optionality and the risk mitigation benefits these efforts might deliver. Decarbonization efforts fall on a decision-making tree, which evolves as time elapses and technology, policy, or other conditions change; each branch of the decision-making tree is a new decision point. Sustainability and asset managers can plan these intervention points over the decarbonization period.
A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.
Building System Conditions
Asset Conditions
Market Conditions
Learn More
Step 2
Step 2: Design Resource Efficient Solutions
Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.
Learn More
Step 3
Step 3: Build the Business Case
Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.
Decarbonization Costs
Business-as-Usual Costs
Business-as-Usual Risks
Decarbonization Value
Net Present Value
Learn More
Strategic Decarbonization Action Plan
An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.
Learn More
Project Team
Additional Resources
Tags
The Empire Technology Prize is a $10 million competitive opportunity for global solution providers focused on advancing building technologies for low-carbon heating system retrofits in tall commercial and multifamily buildings across New York State. This NYSERDA initiative, administered by The Clean Fight with technical support from Rocky Mountain Institute, includes a $3 million sponsorship from Wells Fargo. Accelerating low-carbon building retrofits is fundamental to New York State’s national-leading Climate Act agenda, including the goal to achieve an 85% reduction in greenhouse gas emissions by 2050.
A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.
Building System Conditions
Asset Conditions
Market Conditions
Learn More
Step 2
Step 2: Design Resource Efficient Solutions
Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.
Learn More
Step 3
Step 3: Build the Business Case
Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.
Decarbonization Costs
Business-as-Usual Costs
Business-as-Usual Risks
Decarbonization Value
Net Present Value
Learn More
Strategic Decarbonization Action Plan
An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.
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Insights from Empire Building Challenge
Prioritizing Decarbonization Interventions
While each individual building has a unique capital improvement plan and timeline, retrofit projects or decarbonization interventions may be organized and grouped by similarity as property owners plan for the future. Below is the overarching hierarchy for decarbonization intervention points according to industry best practices:
Facade Upgrades
Windows Upgrades
Ventilation Upgrades with Energy Recovery Ventilators (ERV)
Maximize the reduction of distribution temperatures
Maximize surface area of terminal units
Supplement 90% of peak load with hybrid electrification strategies
Eliminate peak load “last-mile” with innovative strategies in storage and/or thermal demand response
Delay replacement of gas-fired equipment with new gas-fired equipment as long as possible. Rebuild and maintain existing equipment until replacement.
Replace all remaining non-LED lighting and include lighting controls at the time of retrofit
Seal rooftop bulkhead doors and windows.
Add smoke-activated fire dampers or annealed glass to the elevator shaft vent grill in the elevator machine room.
Install algorithmic controls on top of the existing boiler control system.
Balance steam distribution systems:
Identify condensate return leaks.
Right-size air vents and master vents.
Ensure all radiators are properly draining condensate.
Ensure all steam traps are functioning properly.
Implement Radiator Efficiency and Controls Measures:
Install thermostatic radiator valves (TRV) where possible.
Install RadiatorLabs radiator cover systems where possible (integrate with algorithmic boiler control).
Balance air supply and ventilation systems using proper air registers, louvers, dampers, and technology like Constant Airflow Regulator (CAR) dampers:
Need innovative methods of balancing temperature across commercial office floors (heat shifting and sharing from one building exposure to another, e.g. north vs. south).
Balance air supply and return across vertical pressure gradients.
Seal vent stack perforations/leaks (e.g. mastic sealer).
Increase efficiency of pumps and motors:
Add VFD controllers to all pumps and motors.
Replace rooftop exhaust fans (e.g. mushroom fans or similar) with electronic commutated motors.
Implement algorithmic controls on top of existing Building Management Systems (BMS) in commercial office buildings.
Hybrid Domestic Hot Water (DHW) Plants: Add DHW heat pump equipment to an existing gas fired DHW plant.
Consider the option to direct bathroom exhaust air to DHW heat pump equipment.
Install Energy Recovery Ventilation (ERV) system.
Install rooftop solar.
Procure New York State-sourced renewable power.
Procure biomethane from utility via pilot program.
Procure renewable hydrogen blend from utility via pilot program.
Develop innovative means of participating in gas demand response:
Delay boiler firing with controls or other means.
Procure biodiesel blend for fuel switching requirement.
Thermal storage and hybrid plants (electrification)
DHW electrification (partial or full load)
Split system or PTAC partial load heating electrification
Add central-control compatible thermostats to apartments and office suites to control decentralized heating and cooling systems.
Enable aggregate demand response activity.
Fully electrify DHW systems:
Air source DHW heat pump.
Resistance DHW.
High-efficiency thermal storage.
Supplement with solar thermal where compatible.
Overlaid or insulated masonry facades with high ongoing Local Law 11 cost.
Eliminate uninsulated radiator cabinets/niches in exterior walls.
Install wall-mounted slim radiators with TRV or other controls.
Install RadiatorLabs technology.
Begin routine window replacement plan with high-performance windows.
Support cogeneration systems with biomethane (injection) procurement.
Explore hydrogen (injection) procurement to support cogeneration and centralized heating plants.
Develop on-site battery storage systems to manage building load profiles and reduce peak usage.
Integrate with an existing on-site generation where compatible.
Increase thermal mass/thermal inertia and expand thermal storage capacity using Phase Change Material (PCM) products. Products currently include: ceiling tiles, wall panels, AHU inserts, thermal storage tank inserts:
Embrace overnight free cooling.
Shift loads associated with thermal demand.
Capture and store waste heat.
Implement centralized or in-building distributed thermal storage systems to shift thermal loads to off-peak periods.
Convert low-temperature heating distribution systems to shared loop systems or geothermal systems; building distribution is already optimized for low-temperature distribution: water source heat pumps, large surface area terminal units (radiant panels, underfloor heat, fan coils, etc.)
Interconnect with early shared loop system phases (private or utility-led).
Eliminate cooling tower as a primary cooling system (may remain as a backup as feasible).
Where necessary, convert high-temperature heating distribution systems to low-temperature distribution systems; systems converted from fin tube to radiant panels, fan coils, or water source heat pumps as feasible.
The supplement heat source for hydronic heat pumps with solar thermal technology (water source heat pumps).
Embrace consumer products that reduce building loads and peak demand:
Appliances with onboard battery storage.
Networked smart appliances.
Power over Ethernet (PoE) DC-powered, low voltage products.
DC power distribution networks make use of on-site renewable energy and energy storage.
Advanced DC[1] and AC/DC hybrid Power Distribution Systems[2]
Install HVAC Load Reduction Technology:
Capture VOCs and CO2 in liquid sorbent.
Engage with the liquid sorbent management company to safely dispose of scrubbed gases (carbon sequestration, etc.).
Use buildings hosts for negative carbon technology and focusing on direct air capture to achieve larger decarbonization goals (carbon capture and sequestration)
Electric Distribution Upgrade Needed:
Begin replacement of centralized heating systems with decentralized heating and cooling systems where appropriate. Technology includes: PTAC, VTAC, ducted PTAC, VRF, and similar technology.
Replace stoves, ranges, and cooktops with electric equipment: resistance, convection, or induction.
Integrate Building Distribution with an advanced electric vehicle (EV) charging network to provide power to parked EVs and to extract power at peak periods (EV owners opt-in for reduced parking rates, other benefits, etc.).
Install multi-function glass during window or facade replacement:
Install building-integrated PV during facade retrofits.
PV glass.
Electrochromic glass.
Vacuum Insulated glass.
Install highly insulated panels at spandrels:
Vacuum insulated panels.
Aerogel insulated panels.
Replace cooling towers with advanced heat rejection technology:
Passive radiative cooling technology.
Interconnect with 100% hydrogen distribution network.
Pair advanced, on-site battery storage systems with hydrogen fuel cells.
Located in Yonkers, NY, Whitney Young Manor, is a notable affordable housing complex with 195 apartments across 234,000 square feet and 12 stories. Built in 1974, the housing complex is now undergoing a $22 million makeover focusing heavily on decarbonization upgrades. This renovation aims to modernize the buildings by improving insulation and introducing a new heating and cooling system that’s energy efficient. These changes are expected to lower the buildings’ carbon footprint, enhance living conditions, and reduce energy costs. The developer, Paths Development LLC, is leveraging the recapitalization cycle of the property to upgrade its infrastructure and include decarbonization measures to meet its climate goals.
Project Status
Planning
Under Construction
Monitoring & Evaluation
Project Highlights
Investment
12 million
of total investment allocated to bring Whitney Young Manor to carbon neutrality by 2035.
Project Scale
Project has potential replication across a portfolio of 51 existing affordable housing developments managed by Paths.
Testimonial
“The Empire Building Challenge is enabling Paths to pilot innovative approaches to decarbonization while at the same time helping to preserve affordable housing.”
Kenneth Spillberg
Head of Development
Paths Development LLC
Emissions Reductions
This project prioritizes intensive load reduction through envelope improvements and hydronic distribution to improve resident comfort while reducing carbon emissions, utility spend and maintenance costs.
Step 1
Step 1: Examine Current Conditions
A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.
Building System Conditions
Equipment nearing end-of-life
New heat source potential
Comfort improvements
Indoor air quality improvefments
Facade maintenance
Resilience upgrades
Efficiency improvements
Asset Conditions
Recapitalization
Carbon emissions limits
Owner sustainability goals
Market Conditions
Technology improves
Utility prices change
Fuels phase out
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Whitney Young Manor is an aging affordable housing complex with open balconies, inefficient electric resistance baseboard heating, electric wall sleeve AC units, and gas-fired domestic hot water heaters.
The project team believes that with care, planning, and the appropriate resources, retrofitting these residential buildings can better serve tenants, deliver environmental benefits, and prove financially feasible for owners. Paths leverages the recapitalization cycle of the property to upgrade its infrastructure and include decarbonization measures to meet its climate goals.
This project prioritizes intensive load reduction through envelope improvements and hydronic distribution to improve resident comfort while reducing carbon emissions, utility spending, and maintenance costs.
Step 2
Step 2: Design Resource Efficient Solutions
Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.
Existing Conditions
This diagram illustrates the building prior to the initiation of Strategic Decarbonization planning by the owners and their teams.
Click through the measures under “Building After” to understand the components of the building’s energy transition.
Sequence of Measures
2024
2025
Building System Affected
heating
cooling
ventilation
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Reduce Energy Load
Whitney Young Manor demonstrates the benefits of over- cladding and hydronic distribution to enable heat pump technology:
New hydronic distribution: High efficiency water-based distribution system, lower supply temperature
The new hydronic distribution piping will enable the integration of different heating sources and allow heat sharing between end uses, such as DHW production during cooling season. The construction team plans to pilot cross-linked polyethylene (PEX) piping to reduce cost and improve durability.
Dedicated Outside Air System (DOAS): decouple ventilation from heat and cooling systems
Envelope Improvements: overclad, roof insulation and window replacement
Over-cladding using Exterior Insulation and Finishing System (EIFS) helps reduce heat loss and air infiltration while avoiding façade maintenance costs associated with LL11. This measure is combined with the new Dedicated Outside Air System (DOAS) to make sure adequate fresh air is injected into the building.
Recover Wasted Heat
The project team plans to integrate different heat sources connected to the central hydronic piping. This includes centralized air source heat pumps, Wastewater Energy Transfer (WET) system and gas-fired condensing boilers as back-up.
Wastewater Heat Recovery: Recapture heat from wastewater using WSHP
Energy Recovery Ventilator (ERV): Recapture heat from ventilation exhaust to condition make-up air
Electrification
Central Air Source Heat Pump (ASHP): Maintain design temperatures for the hydronic loop
Water Source Heat Pump (WSHP) for Domestic Hot Water (DHW): DHW production supplied by hydronic loop
Back-up gas condensing boiler: Provide supplemental heat during cold events as resiliency
Step 3
Step 3: Build the Business Case
Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.
Decarbonization Costs
$12M
Capital costs of decarbonization measures.
Business-as-Usual Costs
$1.92M
Energy cost savings, repairs and maintenance savings, BAU cost of system replacement and upgrades.
Business-as-Usual Risks
N/A
LL97 emissions fines don’t apply at this property.
Decarbonization Value
$6.14M
Incentives from Empire Building Challenge, Low-Carbon Pathways Program, and ConEd Clean Heat.
Net Present Value
TBD
Net difference between the present value of cash inflows and outflows over a period of time.
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Paths Development LLC is a division of Paths, a full-scale, vertically integrated affordable housing developer, builder, and operator. Since 2004, the Paths team has created and preserved high-quality affordable housing across the U.S. that enhances communities and helps residents build better lives. With other 12,000 units across 9 states under management and more than 300 employees, Paths manages a suite of capabilities spanning the entire property life-cycle, including: development, construction, property management, maintenance, and security.
Strategic Decarbonization Action Plan
An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.
A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.
Building System Conditions
Asset Conditions
Market Conditions
Learn More
Step 2
Step 2: Design Resource Efficient Solutions
Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.
Learn More
Step 3
Step 3: Build the Business Case
Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.
Decarbonization Costs
Business-as-Usual Costs
Business-as-Usual Risks
Decarbonization Value
Net Present Value
Learn More
Strategic Decarbonization Action Plan
An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.
Learn More
Project Team
Additional Resources
Tags
These case studies cover projects that will dramatically reduce carbon emissions with deep energy retrofits for affordable multifamily housing in the Boston area. Deep energy retrofits dramatically reduce carbon emissions. These renovations transform affordable housing to be highly energy efficient, all-electric, powered by clean renewable energy, and renovated with materials low in embodied carbon. These projects are part of the Advanced Building Construction Collaborative’s demand aggregation. This work aims to demonstrate streamlined deep energy retrofits and retrofits using advanced building construction techniques to accelerate the adoption of this work in the market.
