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Low-energy houses have been built in Ireland for more than 13 years. That is at least how long Scandinavian Homes Ltd. have been providing pre-manufactured low-energy Swedish timber-frame houses to the Irish market, the company having been founded in Galway in 1991 by Lars and Linda Pettersson.
At that time these types of houses were considered very radical and the general public was quite sceptical--only one house was sold in the first year. Since then a total of 165 individual houses have been built by our company in Ireland. The emphasis is energy-efficiency and here the Swedish building methods and traditions play a large role. High levels of insulation and an air-tight building envelope in conjunction with ventilation heat-recovery systems and triple glazed low-emission-argon filled glass are important factors.
A cost efficient approach to building low-energy houses must follow rules of simplicity. The designer of a house must be aware of the negative implications of complex architectural shapes. Some features might be culturally correct and fashionable, but we should be aware of their energy consequences. Dormers, roof-windows, bay-windows, long and narrow extensions to the main body, and split levels are all examples of features that cost energy in practice.
The components of a building which are necessary in any case can be optimized for low energy losses, and include the shape and orientation of the building envelope, the performance and orientation of windows and doors, and the performance of the ventilation system.
The standard houses we offer can be described as "low-energy". By optimizing these components further to the point at which a separate heat distribution system is no longer needed yields savings that help finance the extra costs of improvement of the energy performance.
The introduction in 2005 of the completely passive house upgrade redefines what is possible to achieve and sets a new standard of energy-preservation.
A passive house is a house in which heat-losses are reduced to such a degree that no separate heating is necessary. The key elements of a passive house are superinsulation, absolute air-tighness, and elimination of all cold-bridging combined with a heat-recovery ventilation system. The U-values of the exterior building components generally range between 0.1 and 0.15 W/m2C. This standard has been named "Passive House" because the passive heat inputs – delivered externally by solar irradiation through the windows and provided internally by the heat emissions of appliances and occupants – essentially suffice to keep the building at comfortable indoor temperatures throughout the heating period.
It is a part of the passive house philosophy that efficient technologies are also used to minimize the other sources of energy consumption in the building, notably including electricity for household appliances.
A passive house is a building in which a comfortable interior climate can be maintained without active heating and cooling systems. (Adamson 1987 and Feist 1988). Passive house is the most commonly used term for this approach, but terms such as “Zero-energy house”, “Body-heat house” and “House without heating” are different in name, but not in nature.
The criteria for a passive House per m˛ living area include a maximum of 10 W/m˛ constant heating-load , a maximum of 15 kWh/m˛yr annual space-heat requirement and no more than 42 kWh/m˛yr annual total amount of energy input.
Amazing reductions in energy demand and the economic advantage of extremely low running costs are the obvious plus-factors for the passive house concept. As well as this, an ecological building advantage can be recognized. At the projecting stage careful considerations are made for every minuscule detail of the building, with the physical performance, as well as the environmental impact of all materials used being analysed.
The passive house represents the most consistent concept of sustainable building today. During the construction stage the passive house concept requires quality workmanship emanating from a good understanding of the passive principles by all participants. From our experience, this inclusive approach has been highly appreciated by the workmen and has further increased their motivation and work-satisfaction.
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