Blog

By Paul Thompson, BluPath Design

Introduction

In August 2025, Green Building United’s Passive House Community organized and hosted a construction tour of Innova Services Corp’s nearly completed market-rate house. Innova is the developer and contractor for the new three-story single-family rowhome designed by BluPath Design, architects.

Rowhome 2.0, Innova Service Corp’s name for the unique development project, is a market-rate passive building built on spec. This three-story (full basement), four-bedroom project is a South Philly rowhome (with a fabulous roof deck). During the tour, the team presented passive house principles and discussed the challenges of designing and building a market-rate rowhouse to Passive House standards while balancing Innova’s five core values for this project:

1. Extreme Energy Efficiency

2. Occupant Health

3. Low Extraction & Disposal Materials

4. Maintainability

5. Repeatability

Approximately 25 GBU members and guests joined Tom DeLucia, Will Cauffman, and Vaughan Piccolo from Innova, as well as Paul Thompson and Laura Blau from BluPath, as they presented the project, which included the unique systems and materials that distinguish this house from typical market products.

Passive building principles guide the project design

All-electric heat pump HVAC, energy recovery ventilator providing continuous HEPA-filtered fresh air, and heat pump water heater. The induction range has a dedicated exhaust system that extracts air with cooking particles, as well as odors and other cooking-related pollutants, directly from the kitchen. The system turns on when the range hood is turned on. The induction range heats the pans directly using magnetic force. There are no fossil fuels, hence no combustion gases when cooking.

Continuous exterior insulation on all non-adiabatic surfaces. Adiabatic surfaces, such as party walls, are those where no energy is transferred between sides.

Energy use is predicted using the WUFI Passive energy model.

Airtight construction (a measure of quality of construction) was verified by a blower door test on two occasions. The building code requires 5.0ACH (air changes per hour). The final blower door test result was 0.67ACH, 7 times tighter! As noted above, the energy recovery ventilator provides continuous fresh filtered air in this airtight house.

Thermal bridge-free construction reduces condensation risk in the thermal envelope (insulated basement slab, exterior walls, and roof).

Materials and Design

Wood-framed walls, floor, and roof construction on concrete basement walls and footings, with an insulated basement slab.

Vented rainscreen façade with wood and vinyl at sides and rear, brick veneer at front.

• An articulated light-gray brick front façade was replaced with a typical red brick façade due to budget constraints.

Low-impact material selections support Innova’s core values for the project by reducing or eliminating fossil fuel / plastic-based materials.

• TimberBatt wood fiber cavity insulation in place of typical fiberglass
• Aero Aggregate foam glass under the slab instead of foam insulation
• Rockwool ComfortBoard mineral wool insulation instead of polystyrene continuous exterior insulation
• Keim Mineral Silicate Paint in place of acrylic latex paint
• Natural finishing oil in lieu of polyurethane floor finish
• Sassafras domestic rot-resistant wood instead of vinyl siding
• Black Locust domestic rot-resistant wood instead of composite wood deck

Air-tight construction, or Air Control, directly contributes to energy reduction by eliminating drafts, uncontrolled air infiltration, and potential condensation conditions that could deteriorate the structure.

• Taped ZIP sheathing primary air barrier
• Broan ERV for continuous fresh filtered air – in an easily accessible location to change filters.
• Drawing details use color-coded lines to identify the materials and define the continuous airtight envelope connections.
• Penetration details for walls and roof show airtight construction materials and techniques.

Properly designed high-quality fenestration (windows and doors) delivers free solar heat in the winter, reduces solar gain in the summer, and provides comfortable, condensation-free surfaces.

• Rowhouse faces south, no windows on party wall, windows on north wall
• Alpen inswing windows, ‘heat mirror’ triple glazing, insulated frames = PH certified windows
• ThermalBuck, a prefabricated thermally broken structural window opening, ensures a low Psi value, the measure of a quality window installation
• Energy Star entry door with continuous weatherstripping
• Exterior window shading was designed for south-facing windows but was removed due to budget constraints.

Moisture Control

• Airtight, vapor-open wall assemblies, except in basements, allow wall and roof assemblies to naturally ‘sweat’ and dry out, reducing condensation, mold, and deterioration.
• The roof is vapor open to the interior, with vapor-permeable wood fiber insulation at the roof rim boards, below wood nailers, providing continuous vapor-permeable insulation, eliminating thermal bridges and reducing condensation risk.

Conclusion

GBU’s Passive House Community was founded with the idea that passive house design and construction can and should be mainstream. Innova’s Rowhome 2.0 project brings this vision to life: passive building is now achievable and accessible for architects, developers, builders, and potential homeowners.