Paul Archer Design

(173 - user rating)



Sundial Passive House

The basic idea behind Passive House is beautifully simple. Super insulate, stop all the drafts and then use all the ‘free’ heat you can get – be it from human activities or solar gain. Many Passive House designs have been created, but they fall into two primary families. Firstly there are the efficient boxes, with thick walls and small windows. Secondly there are the solar houses, that concentrate most of the glazing towards the sun. Both these models have limitations. The efficient boxes create very internal homes, not dissimilar to medieval houses – dark and inward looking. The solar houses are really only single aspect – great views and light in one direction, but three other aspects tend to be compromised.

First and foremost, a house should be a great place to live. If we let the energy concerns override this basic premise, people will not enjoy living in Passive House homes and they will not be adopted.

Our design proposes a way of combining the best in Passive House energy standards with a light and beautiful modern spaces. Views in all directions, and light from all sides. Starting with the most basic Passive House strategy, we have chosen an architectural form that has a minimal surface area for the volume enclosed – a cylinder (a dome was considered as being even more efficient, but was dismissed as being too expensive to build).

The innovations include

  1. The shutter system. Why fix the thermal performance of the building to match only the winter months. Our proposal is to make the skin of the building adaptable so that the thermal performance of the building skin can be varied between day and night, and from season to season. For example, in winter the northern shutters can be closed and the southern shutters opened to maximise solar gain. The pattern can be reversed in summer to prevent overheating.
  2. Adaptive spaces. By the simple sliding of one partition, the house can be rotated towards or away from the sun. In hot summer months the living spaces can be to the north and enjoy the shade. In the colder winter months, the living spaces can be on the south to gain from any sunshine.
  3. The house sits on a raised earth platform containing a network of ducts, through which the MVHR system draws fresh air into the house. The thermal mass of the earth pre-warms or –cools the incoming air, improving the efficiency of the MVHR heat recovery. The raised platform and pile foundations avoids the need for extensive excavation of the site

Notes on Construction

We wanted a house that could be built using local methods and trades, and avoid unusual specialist technologies where possible. Like many buildings in this part of Europe, the main structure of the house is formed from in-situ reinforced concrete, with a floor slab set on pile foundations and a roof slab supported on twelve columns. The timber-framed outer walls are externally insulated and clad in render and timber boarding, however the design allows flexibility in the choice of structural and cladding materials to adapt to whatever is most easily available or aesthetic preferences. The concrete structure provides thermal mass to stabilise internal temperatures, and the floor slab is exposed to improve the effect of solar gains.

The house is serviced from a central plant room with ducts and conduits radiating out to the various spaces. This keeps the length of service runs to a minimum, improving the efficiency of the systems.

Notes on Site strategy

All material created by excavations for foundations are to be used on site rather than be removed to landfill. The house is then set up on a raised base made of this material. This creates the garden, leaving the rest of the site to natural woodland. It is suggested that this would eventually produce some supplementary firewood, but also gives privacy from your neighbours. A single wall leads from the car port to the house – forming a protected area of garden for vegetables and fruit. This also hides all the utility areas for composting and storage etc.