The journey toward high performance buildings in North America has been shaped by the collaboration of pioneering professionals who refuse to accept limitations. Few partnerships illustrate this better than the engineer architect duo of Lois Arena from Steven Winter Associates and Deborah Moelis from Handel Architects. Their work on some of the continent’s most ambitious Passive House high rise projects demonstrates how technical expertise and design vision can combine to produce buildings that are both beautiful and exceptionally efficient. For those exploring Passive House design and construction lessons from high profile projects, the insights from Arena and Moelis offer a valuable blueprint for what is possible when teams commit to continuous learning and open knowledge sharing.
The Engineer Architect Partnership That Changed High Rise Design
The partnership between Lois Arena and Deborah Moelis represents a model for how engineering and architecture can work in harmony rather than at cross purposes. Arena, a mechanical engineer and Passive House consultant at Steven Winter Associates, brings deep technical knowledge of building performance, energy modeling, and mechanical system design. Moelis, an architect and director at Handel Architects, brings design sensibility, client management skills, and a willingness to push aesthetic boundaries within Passive House constraints.
What makes their collaboration exceptional is the mutual respect each brings to the table. During their presentation at the Passive House Canada Conference in Toronto, titled “Passive House on a Large Scale,” they emphasized that the problem solving mindset is the most important tool any project team can possess. Rather than viewing Passive House requirements as obstacles to good design, they treat each challenge as an opportunity to innovate. Their approach has produced a portfolio of landmark buildings that includes the Cornell Tech student housing tower in New York City, the Winthrop Center residential tower in Boston, Sendero Verde affordable housing in East Harlem, and the University of Toronto Scarborough student residence. These projects showcase how modern methods make high performance building accessible across different building types and budget levels.
- Cornell Tech Tower – The first Passive House certified high rise residential building in New York City, setting the standard for what was possible
- Winthrop Center – A luxury residential tower in Boston that proves Passive House can work at the highest end of the market
- Sendero Verde – One of the largest Passive House affordable housing developments in the world, located in East Harlem
- University of Toronto Scarborough – A student residence that brings Passive House benefits to campus housing
Building a Knowledge Base Through Landmark Projects
The learning curve for high rise Passive House construction has been steep, and Arena and Moelis have been climbing it since the beginning. Moelis admitted that Passive House was not something she originally set out to pursue. She discovered it later in her career, and it transformed not just her professional practice but her personal worldview. Arena described the early project teams as operating like research scientists, facing problems that had no established solutions and figuring them out step by step. This pioneering spirit has been essential because when these teams started, there were few precedents to follow and even fewer certified products available in the North American market. As Passive House Accelerator explains the what and why of Passive House, the standard requires rigorous attention to airtightness, insulation continuity, thermal bridge free construction, and high performance windows. Meeting all five principles at high rise scale demands coordinated effort across every discipline.
The team’s willingness to share lessons publicly has accelerated adoption across the industry. They emphasized during their interview that open sharing of both successes and failures is the only way complex knowledge can be effectively disseminated. The Passive House community has fostered a culture of generosity with information, and this has been critical to the standard’s growth in North America. New practitioners do not need to repeat the same mistakes that early adopters made because those lessons have been documented and shared through conferences, published articles, and direct consultation.
| Project | Location | Type | Key Challenge Overcome |
|---|---|---|---|
| Cornell Tech Tower | New York City | Student Housing | First Passive House high rise in NYC |
| Winthrop Center | Boston | Luxury Residential | Balancing premium finishes with energy targets |
| Sendero Verde | East Harlem, NYC | Affordable Housing | Cost effectiveness at 100% affordable scale |
| University of Toronto Scarborough | Toronto | Student Residence | Cold climate passive house performance |
Overcoming Material and Product Availability Challenges
Six years ago, the window options available for Passive House projects in North America were extremely limited. Arena noted that the market for certified windows has expanded roughly tenfold since then, with fiberglass, uPVC, and improved aluminum options now available. Even more encouraging, storefront and curtain wall manufacturers are beginning to offer Passive House compatible products, which opens up new design possibilities for larger commercial and residential towers. The evolution of thermal break materials has also been significant, with many new products entering the market to address the critical weak points where structural elements penetrate the building envelope. For those working on their own projects, understanding installing high performance windows essential techniques has become much easier as more products and guidance have become available.
Despite the progress with windows and thermal breaks, significant gaps remain in the mechanical equipment market. Arena identified ERVs as the single biggest constraint, noting that teams basically have only one or two choices whether they need centralized, individual, or in suite units. This limited selection makes bidding uncompetitive and restricts design flexibility for engineers. The shortage of cold climate domestic hot water heat pumps is another pressing issue. Arena made a direct appeal to manufacturers to bring these products to the North American market, where demand is growing rapidly.
One particularly compelling idea that emerged from the discussion was the need for a VRF unit that fits into a standard PTAC sleeve. PTAC units are ubiquitous in New York City hotel and apartment buildings, and a drop in replacement that meets Passive House performance levels could transform the retrofit market overnight. Moelis noted that by 2050, approximately 800,000 buildings in New York City alone need to be retrofitted. Having a PTAC sized VRF solution would dramatically accelerate this work by eliminating the need for major structural changes to existing facade openings.
Balancing Design Vision with Performance Requirements
Architects working on Passive House projects often confront a tension between their design aspirations and the technical requirements of the standard. Moelis spoke candidly about this struggle, describing how she works to ensure that Passive House constraints do not dominate her decision making process. When a client wanted a corner window, she initially felt resistance but searched until she found a Passive House certified corner window product. The client got their design vision, and the building still performs. This balance between aesthetics and performance is where skilled architects earn their value.
Arena reinforced that the goal is not to eliminate windows but to use them intelligently. The health and mental benefits of natural light, fresh air, and visual connection to the outdoors are important considerations that must be weighed against energy performance. The key is avoiding extreme design decisions like all glass curtain walls that offer no thermal protection regardless of how high performance the glazing might be. Understanding the Passive House concept means recognizing that comfort, health, and energy efficiency are not competing priorities but complementary goals that can be achieved simultaneously with thoughtful design.
- Start with window to wall ratios that balance energy and daylight rather than pursuing fully glazed facades
- Use thermal break products at every structural penetration to maintain continuous insulation
- Choose high performance windows that match the local climate rather than defaulting to a single product type
- Coordinate mechanical system design early so that ERV placement and duct routing do not compromise the envelope
- Engage the Passive House consultant before schematic design rather than bringing them in after key decisions are locked
Future Opportunities and Advice for New Practitioners
Looking ahead, Arena and Moelis see significant opportunities in building types that have not yet embraced Passive House at scale. Hotels are an ideal candidate because guests value quiet rooms, consistent comfort, and efficient hot water delivery. The first Passive House hotel in the United States will likely prove the model and trigger wider adoption across the hospitality sector. Senior housing is another promising market, particularly in New York City where demand far exceeds supply. The more moderate window to wall ratios typical of senior housing make Passive House certification more straightforward than in luxury residential towers where large expanses of glass are expected.
Universities represent perhaps the most important opportunity for scaling Passive House adoption. Institutions like the University of Toronto and the State University of New York system own massive portfolios of inefficient buildings that need urgent upgrades. Students are increasingly demanding sustainable buildings, and universities have both the institutional commitment and the long term ownership horizon to invest in high performance construction. The student housing projects already completed demonstrate that campus buildings can achieve Passive House certification at competitive costs. These align with fundamental Passive House design principles that prioritize durability, occupant comfort, and operational efficiency.
For architects and builders who want to start their Passive House journey, Arena and Moelis offered straightforward advice. Connect with the Passive House community through trainings, conferences, and online resources. Find out who the experienced consultants and architects are in your area and reach out to them. The Passive House community is remarkably open and willing to share knowledge. Consider running a feasibility study on one of your existing projects to see what it would take to bring it to Passive House certification. The results often surprise teams by showing how achievable the standard is with off the shelf components and a modest number of design tweaks.
Conclusion
The message from Arena and Moelis is clear: Passive House at high rise scale is not only possible but increasingly practical as products improve and knowledge spreads. The building industry is on a trajectory similar to what LEED experienced twenty years ago, moving from early adopter novelty to business as usual practice. The difference is that the learning curve has been compressed because pioneers like this engineer architect duo have been willing to share every lesson they learned along the way. For teams evaluating their options, reviewing green building certification options including Passive House and net zero programs provides context for how these standards complement each other. New practitioners can skip the mistakes of the past and start building high performance buildings today with confidence that the tools, products, and expertise exist to succeed.