The Passivhaus In certain instances, technical environmental standards form part of a movement or contribute to a wider environmental philosophy. The Passivhaus (Passive House) movement, established in Germany in 1996, is a prime example. Initially focused on houses, as its title suggests, the approach has been adapted for public buildings. Passivhaus principles guide the design and construction of buildings that provide a comfortable interior climate that can be maintained without active heating and cooling systems. This is primarily achieved through creating a building that is airtight and through controlling the ventilation by a heat exchanger, so that fresh air brought into the building is preheated with the warmth of the air that is being extracted. The concept also relies on heavily insulating the building thus reducing the heat loss through its walls, floors and roof. The attraction of this approach is that heating costs are virtually negligible without any need for space heating, as occupants provide most of the warmth required to heat the spaces. This could enable huge savings in monetary terms and in C02 production over the life of a building, both very attractive to schools’ governing bodies. Passivhaus buildings are also considered to be healthier as damp, stale air is exchanged for prewarmed fresh air, reducing CO2 levels and airborne contaminants, which is particularly important for young people in schools to maintain their well-being and readiness for learning. In Hanover in Germany, the Postfossil Ecowood Kindergarten [Despang Architekten, 2007] accommodates 70 children and provides living proof of how an ecological benchmark can contribute to a groundbreaking learning environment, where the building design and construction ethos form the backbone of the school’s environmental agenda. The main ethos of the Postfossil Ecowood project is that children growing up in the catchment area of the kindergarten will become some of the first members of a postfossil generation, and that the kindergarten building will be an inspiration to this postfossil community. The new kindergarten replaced an existing building of the same use from the 1950s. The new structure provided an opportunity to rethink the notion of early-years learning as well as creating a community hub with a focus on ecological sustainability. By creating a learning environment with such a high environmental standard, the hope is that the children will not settle for less in the future! The vision for an environmentally integrated kindergarten is borne out through the creation of a building that is at one with its surroundings; curved classroom elements link the building and park, reflecting the curvilinear tree canopies. Within the curved spaces nestles a small group room, echoing the spaces created by tree routes and creating an inspirational space for classes to gather that is inside, yet connected to the outside landscape. As with many Passivhaus projects, the predominant construction material used is timber, both in the laminated timber frame and the external cladding. The building utilises a relatively new type of sustainable heat-treated softwood timber which improves life and increases durability of European softwood to approximately 30 years, without chemical preservative or painting. The northside of the building is a virtually solid wall, dissolving into glazing on the southside. Triple-glazed units make the most of thermal gain in combination with a highly insulated (400mm thick) timber frame structure. Although ventilation is mechanical, there are still openable windows above external doors to provide additional ventilation if required. The cost of constructing the kindergarten was 1800 € per m2 in 2007. Although this initial build cost may be more expensive than a typical kindergarten construction, it is offset by the lower running costs over time. In addition the building offers added value to the school community through its environmental standards.
