Tygh-Na-Cladach - the first Passive House in Scotland is UK's first 'Affordable Housing' Passive House
Overlooking the beautiful River Clyde an unusual project is being completed in Dunoon for Fyne Initiatives: In a row of 10 semi-detached houses, UK’s first 'Affordable Housing' Passivhaus (Passive House) is being build. The finishing touches are being put on ’Tygh-Na-Cladach, which means 'House by the shore'. It was quite a task to get the semi-detached house to reach Passive House levels, since many points, according to the chief planners, had to be fulfilled which are unfavourable for energy efficiency:
Challenges:
- No south-facing windows (apart from 3 rooflights)
- A long, slim and tall shape with relatively small floor space, resulting in a unfavourable ratio between volume and area; i.e. big exterior surface with a lot of heat loss compared to treated floor space
- No mains gas, i.e. electric heating and DHW had to be put in
- Affordable Housing means there was basically no extra-money to be spent compared to a standard house
How it all comes together:
In order to meet these challenges a closed panel timber system from ’RTC Timber’, specifically developed to Passive House levels, has been used for the shell. Thus U-values for the walls and roof where an astonishingly low 0.09 W/(m2K), and the floor sits at 0.12 W/(m2K). Combined with triple glazed windows from ‘Internorm’ and a highly efficient ‘Paul thermos 200DC’ MVHR, Passive House criteria have been met. The heating requirement for the whole house is 1,600 kWh/year. This compares to about 160 litres of heating oil or 160m3 of gas per year, which is approximately a tenth of what an average house of the existing stock uses. To cope with the Passive Houses primary energy requirement limit of 120 kWh/(m2a), a solar thermal system supports the production of DHW – further reducing the energy bill for hot water by over 50%.
Heat Recovery Ventilation:
The house is equipped with a Mechanical Ventilation with Heat Recovery system. The two bed rooms and the lounge room are constantly supplied with fresh air, whereas the kitchen and bathroom are extracted constantly. Before the extract air leaves the house, it passes by a heat exchanger that extracts the heat and transfers it into the fresh supply air. In the image the supply air ducts are shown in red, the extract in blue, intake in green and exhaust in magenta. The heart of the system is a Paul Thermos 200DC MVHR unit with a unique counterflow, crosschannel heat exchanger. The MVHR is Passivhaus certified and has got excellent heat recovery rates of 92-99%. Due to the design of the house the duct runs could be kept quite short.
Air tightness:
Another important feature of a Passive House is the extreme air-tightness, which is required in order to minimize heat loss through the fabric. The aim to achieve a very airtight building with an air tightness below n50=1/h was a challenge for a timber frame building. Thorough planning and detailing by the architect, as well as the careful workmanship of John Brown (Strone) Ltd, the result of the pressure test turned out to be astonishing at just n50=0.38/h (q50=0.4m3/(m2h)). It was the best result the pressure tester had ever seen.
The main players:
Professor Gokay Deveci from the Robert Gordon University has planned the house as architect and wants to showcase that highly energy efficient dwellings can also be built for affordable housing.
The SPHC played a key role in the project, supporting the architect with energy efficiency consultancy and supplying vital Passive House components.
On the 9th April 2010 the certificate as ”Quality Assured Passive House” has been handed over to Fyne Inititives ... the first one of its kind in Scotland!
Meanwhile the excited occupants have moved in 15 Tigh-Na-Cladach. Watch this space for updates!
The Results
Click on any image to view a larger version
