Warm Homes, Lower Bills: York's Passivhaus Success Story

JLM created a highly energy-efficient and environmentally sustainable housing scheme comprising 108 new timber-framed houses across two sites that met rigorous Passivhaus standards, ensuring minimal energy consumption for heating and cooling, airtightness, and reduced carbon emissions.

The project aimed to integrate renewable energy systems, such as Solar PV and air source heat pumps, while addressing environmental concerns, like protecting local wildlife and maintaining the aesthetic and functional integrity of the development. Ultimately, the project sought to provide high-quality, sustainable housing that contributed positively to the environment and community.

Key Project Innovations:

Integration of Multiple Advanced Systems:

The project required integrating several advanced mechanical and electrical systems—Solar PV, air source heat pumps (ASHP), and multi-vent heat recovery (MVHR) systems—within each of the 108 timber-framed houses. The challenge was not only in the installation but in ensuring that these systems worked harmoniously to meet passive house standards.

Airtightness with Timber Frame Construction:

Achieving the level of airtightness required for passive house certification in a timber-framed structure posed significant challenges. The use of specialised membrane tapes, grommets, and meticulous installation techniques was necessary to prevent air leakage and thermal bridging, which are more typically encountered in more traditional passive house constructions using concrete or masonry.

Bat-Friendly External Lighting:

The design of an extensive external lighting scheme that was specifically tailored to be non-disruptive to local bat populations was a unique environmental consideration. This involved using lighting technology and placement strategies that are not commonly required in standard construction projects.

Comprehensive Lightning Protection for Solar PV Arrays:

Including vast in-roof solar PV systems required a robust and extensive lightning protection strategy. This was an unconventional requirement given the scale and exposure of the PV arrays, necessitating specialised surge protection devices and grounding systems beyond what is typically required in residential developments.

Pre-Insulated Pipe and Duct Installations:

Using pre-insulated pipes and ducts for the ASHP and MVHR systems was a novel approach to ensure energy efficiency and maintain the overall airtightness and thermal performance of the building envelope. This required careful planning and installation to avoid compromising the building’s energy performance, which is a more complex undertaking than in conventional housing developments.

Specialised Research and Development:

The project demanded a level of R&D that went beyond typical residential construction. This included custom-designed systems, materials, and methods to ensure that all components met the stringent requirements of passive house certification while addressing unique environmental and structural challenges.

Major Challenges Addressed:

Integration of Advanced Systems:

Incorporating Solar PV systems, air source heat pumps (ASHP), and multi-vent heat recovery (MVHR) systems into each of the 108 houses was complex. The challenge was not just in installing these systems but ensuring they worked together seamlessly to achieve the stringent energy efficiency and comfort levels required by passive house standards.

Achieving Airtightness in Timber-Framed Structures:

Timber-framed buildings are inherently more challenging to seal than other construction methods like masonry or concrete. Ensuring airtightness to meet passive house criteria required meticulous attention to detail, the use of specialised membrane tapes and grommets, and careful coordination of all trades involved in the construction process. Any mistakes could compromise the entire building’s energy performance.

Eliminating Thermal Bridging:

Preventing thermal bridges in construction was crucial to maintaining energy efficiency and indoor comfort. The challenge was to design and install systems such as ductwork, piping, and structural elements in a way that avoided creating paths for heat loss, which is particularly difficult in timber-framed constructions.

Environmental Considerations and Bat-Friendly Lighting:

Designing an external lighting system that was non-disruptive to the local bat population added an environmental layer of complexity. This involved selecting specific lighting technologies, optimising light placement, and integrating sensors to minimise lighting duration, all while ensuring that the lighting scheme met safety and usability standards for residents.

Lightning Protection for Solar PV Systems:

The expansive in-roof Solar PV installations increased the risk of lightning strikes. Designing and implementing an effective lightning protection system that would safeguard both the PV systems and the buildings required a comprehensive and technically sophisticated approach. This challenge was compounded by the need to protect these systems without compromising the building’s aesthetic or energy performance.

Pre-Insulated Pipe and Ductwork Installation:

Installing pre-insulated pipes and ducts for the ASHP and MVHR systems required precision to ensure they did not compromise the building’s airtightness or thermal performance. The routing and sealing of these services were particularly challenging, as any gaps or poorly insulated sections could lead to significant energy losses.

Coordination and Quality Control:

Ensuring that all aspects of the project met the passive house standards required rigorous coordination between different trades and meticulous quality control throughout the construction process. This was particularly challenging given the need for high precision in installing airtightness measures, system integration, and environmental protection.

Meeting Passive House Standards:

The overall challenge of meeting passive house certification standards across all 78 units was a significant difficulty. This required ongoing testing, adjustments, and validations at various stages of construction to ensure compliance with the strict energy efficiency and indoor climate requirements.

These challenges required innovative solutions, careful planning, and a high level of craftsmanship to ensure the project’s success.

Discover the future of energy-efficient living! Learn more about Passive Homes and their role in achieving net zero buildings.

JLM specialises in providing innovative renewable energy solutions tailored to the unique needs of the commercial sector.