Derwood Passive House

Project Description

Nestled in the community of Derwood, a charming home stands out not just for its quaint cottage aesthetics but for its adherence to rigorous passive house standards. This project was a pioneering effort in the area, aiming to blend traditional design with cutting-edge energy efficiency.

The Challenge:

The challenge was to construct a home that met the stringent requirements of a passive house, ensuring ultra-low energy usage without compromising on the comfort and style of a classic cottage. Achieving such a delicate balance between old-world charm and modern efficiency required careful planning and execution.

Project Details

Designer Alan Abrams – Abrams Design Build
Photo Credits Lisa Rigazio
Date of Completion 2015
Skills Passive House, Ultra Energy Efficient

The Transformation:

  • Energy-Efficient Foundation: The house is built on a concrete slab, beneath which lies 9 inches of insulation. This foundation is crucial for minimizing heat loss and is a cornerstone of the home’s energy-efficient design.
  • Airtight Construction: Achieving an impressive 0.6 ACH (Air Changes per Hour) in the blower door test, the house far exceeded typical standards of the time. This level of air tightness is essential in maintaining consistent temperatures and reducing energy demand.
  • Cottage Aesthetics: Despite its high-tech heart, the exterior exudes a quaint, cottage feel. The use of shakes for siding and an inviting front porch with elegant columns perfectly capture the traditional cottage essence.
  • High-Performance Windows and Doors: Sourced from a passive house-approved manufacturer in Eastern Europe, the windows and doors are not only aesthetically pleasing but also incredibly efficient. Their heavy-duty construction and superior insulation properties (measured by U-factors) significantly contribute to the home’s overall energy performance.
  • Long-Term Commitment: The decision to import specialized windows and doors reflects a long-term commitment to energy efficiency and sustainability. While the logistics were complex and time-consuming, the end result was a home with unparalleled insulation and airtightness.


The Derwood Passive House stands as a beacon of energy efficiency, wrapped in the warm, inviting style of a traditional cottage. Its impressive performance in the blower door test and the use of high-efficiency materials set a new standard for sustainable residential construction in the area. The home not only provides a comfortable and beautiful living space for its inhabitants but also serves as a case study in successfully marrying old-world charm with cutting-edge building science.

Innovative projects that stand the test of time.