A Landmark in Sustainable Building: The Den Passivhaus
The Den, a newbuild timber frame detached house, stands as a testament to sustainable and energy-efficient construction. As Dorset's first certified Passivhaus, this remarkable project was designed by Conker Conservation and built for clients Dennis and Nicola Merrigan. Dennis, a chartered surveyor and seasoned building professional, personally undertook the construction, an experience that led him to establish MINT Construction Services Ltd. His company now specializes in assisting clients who wish to build to the stringent Passivhaus standard.
Superior Insulation and Structural Integrity
The Den's robust construction features walls and a roof insulated with recycled cellulose fibre. To ensure exceptional thermal performance, triple-glazed windows and rooflights are installed throughout the house. A crucial detail for minimizing thermal bridging—a common cause of heat loss—is the external layer of wood fibre insulation that meticulously overlaps all windows and doors. With a floor area of 158.6m2, the house achieves an impressively low space heating demand of just 12 kWh/m2/year. The home's sole space heating source is a Passivhaus-approved wood-burning stove, complemented by an electric water heating system.
Advanced Heat Recovery Ventilation by 21 Degrees
A key component of The Den's energy efficiency is the PAUL Novus 300 MVHR (Mechanical Ventilation with Heat Recovery) system, which was designed, supplied, and commissioned by 21 Degrees. Conker Conservation's recommendation of this advanced system proved to be an excellent choice.
According to Dennis Merrigan, the system is "very quiet and straightforward to operate," with maintenance limited to simple filter changes. The project, completed in 2013, benefited from 21 Degrees "very helpful" MVHR department, and the use of rigid steel ducting was particularly appreciated for its durability and robustness. The MVHR system plays a vital role in maintaining a constant supply of fresh, filtered air while recovering up to 90% of the heat from the outgoing stale air, a core principle of Passivhaus design.
Dennis Merrigan
The system has now been in operation and use for several years.
Dennis Merrigan
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Project details
Architect
Completed
2013
