There are considerably easier ways to construct a high-performance building than starting with a brick rowhouse dating back more than 100 years inside a protected historic district. In truth, industry experts agree that undertaking a historic urban retrofit to meet elite energy standards is arguably the most arduous path available.
Nevertheless, a visionary homeowner working alongside a specialized general contractor and a meticulous HVAC specialist in Lancaster, Pennsylvania, set out to prove it was entirely possible. The project transformed a late-19th-century, three-story, 2,200-square-foot brick rowhouse into a certified Passive House masterpiece.
Achieving this required navigating a maze of severe structural limitations. Shared party walls on the east and west, strictly protected front masonry facades that precluded exterior insulation blankets, severely restricted mechanical pathways, and minimal ceiling clearances in the basement presented monumental obstacles. Yet, through extraordinary collaboration between Jesse Pellman, co-owner of Longview Structures, and Dustin Ebersole, founder of High Efficiency Solutions, the team not only met but exceeded the rigorous performance metrics required for Passive House certification.
The finished home relies on a single, two-ton Fujitsu AIRSTAGE Aquila XLTH multi-zone mini-split system as its sole source of heating and cooling. Backed by an advanced 200-CFM Panasonic energy recovery ventilator (ERV) and a comprehensive air-sealing strategy, the home shattered traditional performance expectations. A whole-home blower door test recorded an astonishingly tight envelope of 0.3 Air Changes per Hour (ACH) at 50 Pascals—well below the strict 0.6 ACH Passive House threshold. Coupled with a planned photovoltaic solar array, the century-old rowhouse is projected to achieve net-zero energy status.
Chronology of the Retrofit: From Blueprint to Turnover
The journey to transform a historic Pennsylvania home into an ultra-low-energy sanctuary was a multi-year endeavor characterized by meticulous planning, rigorous execution, and constant cross-trade coordination.
Phase 1: Early Design and Feasibility (Two Years Prior to Completion)
The project began more than 24 months before its final turnover. During this initial phase, Pellman and Ebersole confronted the stark reality of historic-district restrictions. The front facade could not be altered or wrapped in modern exterior insulation, eliminating a standard tool used in modern retrofits.
In early 2025, Ebersole brought architectural blueprints, meticulous heat load calculations, and site-specific hurdles to Eric Weik, regional sales representative at Johnstone Supply (The Wallace Group) in Lancaster. Together, they mapped out an HVAC architecture that could navigate tight physical spaces while delivering the precise conditioning necessary for a multi-story layout featuring a third-story wellness retreat complete with a steam shower and sauna.
Phase 2: Shell Tightening and Thermal Envelope Execution (Summer 2025)
By the summer of 2025, physical construction and building envelope remediation were underway. To achieve the necessary airtightness without compromising the historic brick exterior, crews applied a fluid-applied Visconn membrane directly against the interior face of the exterior masonry. This was reinforced with specialized tapes, sealants, and a redundant interior layer of Intello Plus variable-permeability air and vapor control membrane.
Insulation strategies were similarly multifaceted. The construction team deployed three distinct types of insulation throughout the floorplan: rigid Rockwool, sustainable lamb’s wool batts, and dense-pack blown cellulose. To further optimize the envelope and eliminate drafts, Longview specified triple-pane Optiwin windows, no-VOC paints, and extensive natural building materials. Thermal modeling was continuously conducted to predict and mitigate potential condensation risks within the historic wall assemblies.
Phase 3: Mechanical Rough-In and Ductwork Integration
Installing mechanical systems in a three-story rowhouse with limited ceiling heights demanded extreme ingenuity. Ebersole’s crew utilized extensive runs of metal oval ductwork, compressing them into tight vertical and horizontal cavities where traditional round ducts could never fit.
Simultaneously, the High Efficiency Solutions team coordinated with third-party Passive House verifiers who conducted periodic jobsite inspections. Crucially, the custom ductwork installation passed its rough-in pressure test on the very first attempt—a rare feat in historic retrofits where minor leakage is often tolerated.
Phase 4: Final Commissioning and Verification (September 2025)
By mid-September, the transformation was complete. Final blower door tests, air balancing, and energy verifications confirmed that the building met all Passive House criteria. When the mechanical systems were activated and the ERV brought online for the first time, the interior air quality shifted dramatically, signaling the successful birth of a high-performance home housed within a century-old shell.
Supporting Data and Technical Specifications
The engineering marvel of this Lancaster rowhouse lies in the harmonious interplay between its hyper-insulated building envelope and its remarkably compact mechanical systems.
HVAC System Architecture
Primary Heat Pump: Single, two-ton Fujitsu AIRSTAGE Aquila XLTH (extra low temperature heating) multi-zone mini-split system.
Heating Capacity at Extremes: R-32 refrigerant-based system capable of delivering reliable heating down to outdoor temperatures of -15°F, easily surpassing Lancaster’s design-day requirements.
Connected Capacity: 31,000 BTUh of connected indoor capacity tied to a 24,000 BTUh nominal outdoor unit, utilizing the system’s 130 percent connection flexibility.
Indoor Distribution Zones:
Wellness Room: 7,000 BTUh wall-mounted unit on the third floor.
Main Living Space & Second Story: 12,000 BTUh Multi-Position Air Handler (MPAHU) handling heavy solar gain areas.
Basement & Ground Floor: 12,000 BTUh slim-duct air handler tucked neatly into a basement closet.
Ventilation and IAQ Systems
ERV Unit: 200-CFM Panasonic Energy Recovery Ventilator located in the basement mechanical room, supplying fresh pre-conditioned air while exhausting stale air from bathrooms, the kitchen, and the wellness area.
Moisture Management: An integrated Innovative Dehumidifier in-wall unit serving the third-story wellness space, with all indoor units and the dehumidifier gravity-draining to a central condensate pump.
Building Envelope Metrics
Blower Door Test Result: 0.3 ACH at 50 Pascals (surpassing the Passive House standard of $le$ 0.6 ACH).
Fenestration: Triple-pane Optiwin windows designed for maximum thermal resistance and solar heat gain control.
Air Barriers: Visconn fluid-applied exterior masonry membrane paired with Intello Plus interior variable-permeability control layers.
Official Responses and Industry Perspectives
The project’s success relied heavily on the synergy between experienced trade professionals who viewed the challenge not as a burden, but as an opportunity to push the boundaries of modern construction.
Jesse Pellman, co-owner of Longview Structures—a company founded in 2008 with a reputation for self-performing craftsmanship and LEED Gold standard construction—reflected on the intense nature of the build:
"We wanted to find out if we could make this happen. Nobody accepts a five percent leak in a plumbing system, but small losses are generally ignored—if even tested—in conventional HVAC systems. Not so on a Passive House project. The early-stage planning is so critical. We knew how important it was headed into the project, and we still underestimated it."
Dustin Ebersole, founder of High Efficiency Solutions, who has partnered with Longview on numerous historic farmhouse and urban renovations since 2011, emphasized the shift in accountability required for such high-stakes builds:
"Passive House projects require a lot more testing, verifying, and working with third-party verifiers than I expected. More accountability is required, not just to your client, but to the verifiers. That accountability extends across everyone on the jobsite."
Commenting on the performance of the Fujitsu AIRSTAGE equipment, Ebersole added:
"Distributor-level tech support for AIRSTAGE equipment is great. It’s just a very well-supported brand. They also offer a wide variety of indoor units, which was critical to making this project work. It’s extremely impressive that this entire home can be heated and cooled by a single, two-ton multi-zone. That speaks volumes about how far heat pump technology has come, but also about how tight Longview was able to make this old house."
Recalling the moment the ventilation system was first engaged, Ebersole noted:
"When the house was sealed, and the ERV was turned on for the first time, workers inside clearly noticed the difference. Because the building envelope is so tight, we felt as if we’d been working inside a trash bag. Turning on the ERV changed the environment dramatically. It provided fresh air."
Eric Weik, regional sales representative at Johnstone Supply (The Wallace Group) in Lancaster, played an integral role in selecting the precise hardware configuration. By pairing detailed blueprints with comprehensive heat load calculations, Weik ensured that the equipment specified could deliver maximum efficiency without overstepping the strict physical boundaries of the historic floorplan.
Broader Implications for Historic Retrofits and Sustainable Building
The successful certification of this 100-plus-year-old Lancaster rowhouse carries profound implications for the future of urban architecture and sustainable real estate. Across historic American cities, countless aging brick rowhouses sit drafty, energy-inefficient, and dependent on fossil fuels. Historically, municipal historic preservation boards and the rigid physics of century-old construction have discouraged deep-energy retrofits.
This project proves that preservation and ultra-high-performance building are not mutually exclusive. However, it also serves as a cautionary tale for builders who treat green construction as a checklist-based afterthought. Passive House is an absolute performance standard. It punishes poor communication, uncoordinated duct routing, and sloppy air-sealing.
For the HVAC and general contracting industries, the Lancaster rowhouse underscores several critical takeaways:
Early Cross-Trade Collaboration: Mechanical contractors cannot afford to enter a project after framing and insulation are complete. Duct layouts, ERV intake locations, and condensate drain paths must be engineered concurrently with architectural and thermal plans.
Technological Maturity: Modern variable-capacity heat pumps, such as extra-low-temperature multi-zone mini-splits, have reached a level of efficiency and thermal output capable of heating entire multi-level structures in cold climates without supplementary fossil fuel backups.
The Whole-Building Ecosystem: A high-performance home cannot rely on a single superstar component. The insulation, windows, airtightness membranes, heat pumps, and ventilation systems must operate as a singular, interconnected living machine.
As energy codes tighten and homeowners increasingly seek sustainable living solutions in urban cores, the Lancaster rowhouse stands as a beacon of what is possible. It demonstrates that with skilled craftspeople, advanced HVAC engineering, and uncompromising dedication, America’s architectural past can be successfully harmonized with its sustainable future.
