"Out of the Blue" Passive House

Built in 2004, Tomás O’Leary's "out of the blue" house in Wicklow was the first in the country to be certified by the Passive House Institute. It was designed by MosArt Architecture and is officially certified as a Passive House by the German Passive House Institute and is being intensively monitored by the Energy Research Group at UCD for a period of two years to measure performance in terms of energy efficiency. The house is extensively featured in the recent SEI Passive House Guidelines and has provided inspiration for many others to build passive Houses in Ireland. 

 

The passive house concept is based on minimizing heat losses and maximizing heat gains from the home. This is achieved through reducing heat loss with insulation and by making the house airtight, and increase heat gains by maximizing solar heat gains through design & orientation. The house is 365 m2 with average ceiling heights of 2.7m. It is a 2-storey Single family detached dwelling with 5 occupants.  The house construction comprises a 225mm concrete block wall externally clad with 315mm of polystyrene insulation, achieving high thermal mass. The buildings glazing compromises triple glazed window units with u-values of 0.6 W/m2K. The frames are thermally broken and made from wood. The floor construction has 315mm of Polystyrene insulation below a 150mm concrete slab. The house is passively heated and utilizes a heat recovery ventilation system . A biomass wood pellet stove is used as a backup heating system in case of extreme conditions.

Steps for a Passive House in your region with your climate

In the first step of this article by Dr. WolfgangFeist, he talks about how Passive House is not a style of building but more of a method of achieving a better performing house. The method of constructing a passive house is heavily dependant on the geographical location of the site as the climatic conditions are a major factor in the performance of a passive house. The local building traditions & specific climatic conditions have to be considered when designing a passive house for a specific region. Passive House methods can vary from region to region as climates differ in different parts of the world. Dr. Wolfgang Feist uses the example of Passive House methods in California used in Europe proved unsuccessful due to differences in solar gain in the two regions.

However, the principles of passive house remains the same throughout the world. The Passive House principle is based on the concept by Amory Lovins of reducing investment through energy efficient design. It is suggested that when the peak heating load of 10W/m2 is reached it is a significant threshold. The definition of a Passive House is the peak heating load should be projected to a lower level than 10W/m2. The construction costs of trying to achieve a Zero Energy House can outweight  the benefits, It is much more logical to strive for a passive house that has low energy consumption.

The methodology for passive house solutions always remain the same:

• Use passive technologies to reduce peak load demands 
• Use heat recovery for good indoor air quality and heating 
• Maintain high comfort levels
• Use affordable, cost effective, simple solutions to minimise energy demand. 
• Always provide insulation
• Provide shading in areas with high solar radiation
• Provide heat recovery in all climates for heating, cooling and dehumidification 
• Geothermal systems can provide heating and cooling depending on the region

The next step is to perform a computer based parametric study of the building design solutions and to check the results for energy demands, financial investment, and healthy indoor climate.  The different elements of a traditional house can be modified step by step to achieve passive house standard. The parametric study is performed using computerised thermal building model.