Lena Gardens Passivhaus

Lena Gardens Passivhaus

The Project

The challenge for low energy house designers Princedale Ecohaus and Green Tomato, was to find solutions which would allow the three storey terrace house to perform to the very high levels demanded by the Passivhaus standard.

This involved designing and developing all of the systems used in the house, including the airtight wall configuration.

Kingspan Kooltherm K7 Pitched Roof Board, Kooltherm K12 Framing Board and Thermawall TW55
Princedale Homes and Green Tomato Energy

Due to the terrace being located in a conservation area, all insulation had to be installed internally. Our Kooltherm range was chosen for the project as relatively thin layers of insulation could be used to achieve the very high levels of thermal performance needed.

To make the house airtight, a continuous layer of OSB was installed on the roof, all external and party walls and the lower floor. Airtight tape and breathable membranes were then used to seal the OSB layer to the windows and doors, forming an airtight barrier and allowing the building to meet the required Passivhaus air tightness limit of 0.6 m³/hr/m² @ 50 Pa.

Our client wanted to convert his house into a home fit for the future. Installing highly efficient, space-saving Kingspan Kooltherm allowed them to achieve this whilst minimizing the loss of internal space.

Tom Packenham - Director, Green Tomato Energy
On the external walls 130 mm and 50 mm thicknesses of Kooltherm K12 Framing Board were fitted either side of the airtight barrier, while on the roof a 130 mm layer of Kooltherm K7 Pitched Roof Board was installed between the rafters, with the airtight barrier and a second 50 mm layer fitted under the rafters. The finished roof and external walls produced an outstanding thermal performance with U-values of only 0.10 W/m²·K. To further insulate the building a 50mm layer of Kooltherm K12 Framing Board was also installed on the party walls.

By combining these measures with a heat recovering mechanical ventilation system, the house now needs less than 15 kWh per m² of energy to be heated annually, far lower than the UK single family home average of 130 kWh per m².
The benefits of retro-fitting houses to the Passivhaus standard are tremendous. Not only are the annual heating bills for most houses reduced to less than £100, but the combination of an airtight barrier, insulation and airtight triple glazing and mechanical ventilation mean that nuisance outside noise such as traffic can be easily shut out, creating a tranquil environment within the house.

Phillip Proffit - Director, Princedale Homes
The house in Lena Gardens is one of two that have been retrofitted by Princedale Homes to Passivhaus standards in the UK. The other property to have achieved this status thanks in part to our high performance insulation is a Victorian terrace house in Princedale Road, London.

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