The term ' Passive House' has become more commonly used in the UK in recent years, largely as a result of increased media coverage on radio and television programmes, such as Channel 4' s Grand Designs. With the mounting pressure to reduce our CO ² emissions, whilst also becoming more sustainable and energy efficient in line with Government objectives, could this rigorous German energy standard help us to reach our ambitious targets for 2016 and beyond? The Passive House Concept A Passive House is a building that is designed and constructed to a strict set of criteria to ensure maximum comfort with minimum overall energy consumption. The building fabric is detailed in such a way that heat loss is reduced to an absolute minimum, whilst internal heat gains are maximised. As a result, conventional heating systems can be removed and space heating can sufficiently be supplied through passive sources such as body heat and the sun. This saves up to 90% of the building's overall energy consumption when compared to a standard house constructed to current Building Regulations. The Passive House Institute The Passive House approach is tried and tested and is widespread in both Germany and Austria. The first Passive House project was built in Germany in 1990 and there are now an estimated 20,000 Passive Houses across Europe. The Passive House Standard: An Introduction To live in the most environmentally friendly way, a Passive House is perhaps the way forward. Certified Passive House Designer, Steff Bell Bsc ( Hons) ACIAT explains how they work in the first instalment of his introduction to the Passive House Standard. PASSIVEHOUSE 14ATMARCH- APRIL2010 Right: Passive House example from Steingaden, Germany ( South elevation)

The Passive House Institute ( PHI) was founded in 1996 by the concept's co- creator Professor Wolfgang Feist. Based in Darmstadt, Germany, the institute have developed the Passive House Standard through extensive research and monitoring of thousands of Passive House projects. The success of the Passive House Standard in Europe has been, in part, due to the expert guidance and certification schemes lead by the PHI, and also thanks to the backing of the EU and respected professional institutions that have embraced the Standard. European projects such as CEPHEUS ( Cost Efficient Passive Houses as European Standards) and PEP ( Promotion of European Passive Houses) have been launched to assess the potential of the Passive House Standard with regard to providing affordable, low energy homes as standard across Europe. These projects have been very successful and have played a large role in the development and progression of the Passive House Standard. Passive House Design A building designed to Passive House Standards will provide a number of benefits for its owners andor tenants. Such benefits will include excellent indoor air quality with reduced internal pollutants and a constant supply of fresh air, a reduction in maintenance and running costs as well as a drastic reduction in energy consumption and CO ² emissions. Passive House Criteria and the Passive House Planning Package ( PHPP) The basic principles upon which the Passive House Standard has been developed centre around a set of strict criteria that every Passive House project must adhere to in order to become a certified Passive House. The main criteria are as follows: . Space heating demand = 15 kWh/( m ² a) . Building heating load = 10 W/ m ² . Useful cooling demand = 15kWh/( m ² a) . Primary energy demand = 120kWh/( m ² a) . Building air- tightness = 0.6 ac/ h  ¹ . Excess temperature frequency = 10% Compliance with these criteria is verified using the Passive House Planning Package ( PHPP) throughout the design and construction process. The PHPP is a sophisticated design tool specifically developed by the PHI for the accurate planning and calculation of Passive House buildings. The PHPP is similar to SAP, however PHPP is considerably more advanced with the ability to provide accurate results that have been proven through extensive monitoring of existing Passive House buildings across Europe. In addition to the PHPP calculations, there are a number of sub- criteria and design considerations to be taken into account when planning a Passive House Project that It is possible to build a Passive House to the same price as a house built to current Building Standards in the UK PASSIVEHOUSE ATMARCH- APRIL2010 15 Below: Passive House example from Steingaden, Germany ( South elevation)