Passive House Design

Passive House represents today's highest energy standard with the promise of reducing the energy consumption of buildings by up to 90% while providing superior comfort and air quality -- all at minimal additional upfront cost. When coupled with renewable energy systems, such as solar and wind, Passive House puts true zero energy buildings within reach.
The concept originated from Germany and was first put to test in 1991. It has been tried, tested and improved on each year since. In Germany alone there are over  10,000 passive house examples in both domestic and commercial buildings.

Plans

IBER has first hand knowledge and experience in carrying out all the design elements of the passive build (PHPP), sourcing local materials to carry out the build and most importantly can offer on site supervision/training to ensure all calculated details are achieved on site.

Concept

Passive House is a building standard that relies on a combination of energy efficiency, passive solar and internal heat gains to eliminate the need for a conventional heating and natural ventilation system. The concept is implemented through stringent performance standards for airtightness and energy conservation and verified with a field tested energy modelling program, the Passive House Planning Package (PHPP). The energy consumption limits are developed through extensive research on climate change imperatives, economic feasibility, building durability, occupant comfort, and indoor air quality.

The principle is quite simple. A conventional house loses a lot of heat out of its walls, windows, doors, floors and roof, which needs heat pumped into it constantly to keep the temperature at a comfortable level.

A Passive House is a very well insulated, virtually airtight building that is primarily heated by passive solar and internal heat gains from occupants, cooking, bathing, electrical equipment, etc. Over heating in summer is controlled through shading, window orientation and passive ventilation helps to limit the cooling load. Any backup heating or cooling demand is provided by an extremely small source instead of a conventional heating / cooling system. Heat Recovery Ventilation provides a constant supply of tempered, filtered fresh air. Using this “fresh air” heating and cooling system not only saves space conditioning costs by “recycling” indoor energy, it also provides excellent indoor air quality and consistent comfort.

Ergonomics

Passive houses typically cost 10% more than conventional building standards (TGD L 2005). It is considered to be some what less than 10% now as the new building regulations will cost more to build than previous 2005. Some of the additional expense can be recouped by saving capital on a conventional heating system, which can typically cost up to €20,000. Heat Recovery Ventilation replaces the requirement for Radiators and Underfloor heating as it now carries two jobs both ventilation and also delivering the heat, via a duct heater. With a backup heating system typically 1/5 the size of a conventional boiler/heatpump, various methods of supplying this minimal amount of heat can be considered. As little as a 2kW electric blow heater would be sufficient to heat a 250m2 passive built home! One candle emits 10 Watts, 200 candles could heat this same house!

Future Proof

While creating a new building may be the biggest investment you may ever make, typically spread over 25 to 30 years it is worth considering the future value of your property. Just take a look our current status in Ireland; Ministers have introduced enforcement on all new dwellings which must produce 40% less energy and carbon relative to Technical Guidance Document Part L (TGD L) conservation of fuel and energy 2005. 10kWh/m2yr of heat or electrical energy must also be produced by a renewable energy source. The Minister has released plans on introducing a further 60% reduction in 2010 and “Zero Carbon” standard by 2013, meaning all new dwellings would be self sufficient! It is clearly seen that by taking the plunge at the early stages you will benefit from increased property value, low carbon taxes (should they be introduced) and a house of the future.

Chart 1
Graph 1

Graph 1 above illustrates how our current situation TDG L 2008 compares to the passive standard requiring under 15kWh/m2yr of heat energy.

Chart 2
Graph 2

The Ministers plan (Graph 2) emphasises the importance of how passive design and renewable energy production will be combined to achieve Zero Carbon Status in the near future. Zero Carbon is currently achievable as referance dwellings in Ireland are currently appearing. Look no further than IBER’s First Carbon Neuteral passive House. Not only is it carbon neutral, but the dwelling will operate in minus figures of carbon as it becomes a nett producer of electricity! See Current News

Chart 3
Graph 3

Comparison of delivered energy in conventional house and in a house built to Passivhaus Standard.Source: Passivhaus Institut. http://www.passiv.de

Passive Requirements:

The construction of a passive house is very demanding in terms of the performance of the materials used and the attention to detail in fitting them. The following are some of the design criteria which must be meet;