The design principles of the Passive House (PH) are becoming increasingly popular in Australia, yet their uptake has been much slower than in Europe where the concept originated. PH is a building standard or a construction concept that was developed by Dr. Wolfgang Feist of the Passivhaus Institute in Germany. The first PH – built in Darmstadt, Germany in 1990 – was the first multi-family house in Europe to achieve a documented heating energy consumption of below 10 kWh/(m²a).
In order to achieve passive house certification, a building must meet four key performance measures as set by the Passivhaus Institute in Germany. These include parameters for Space Heating Energy Demand, Renewable Primary Energy Demand, Air Tightness, and Thermal Comfort. These requirements go well beyond the traditional Australian Standards for building design and performance.
Despite the construction of a number of accredited Passive Houses in Australia, there is reluctance from the industry to adopt the standard entirely for several reasons. This includes, but is not exclusive of, its initial outlay costs and unfamiliar building methods, and it’s requirement for hermetically sealed building envelopes, which are considered unsuitable for Australian climates and living arrangements.
That’s not to say the merit of the standard and its performance criteria hasn’t been acknowledged by Australia’s AEC sector. On the contrary, it’s space heating energy demand requirements of 15kWh/sqm per year and renewable primary energy demands are both recognised in Australia as very high, and far outstretch our base requirements as set out in The Nationwide House Energy Rating Scheme (NatHers). NatHers rates homes out of ten stars based on an estimate of a home’s potential (heating and cooling) energy use and determine a six-star rating as the base requirement for a house. In a climate like Melbourne’s, a six-star rated home would require 32kWh/sqm per year for heating and cooling.
The space heating performance of Passive House can be achieved in Australia using Australian products and traditional construction methods. Popular energy sources for Passive Houses include gas boilers, solar heating, radiant heating and geothermal pumps, most of which are readily available from Australian suppliers.
Floor heating systems for one, are an energy efficient and cost effective radiant heating system, which are popular in Australia where open plan houses are common. Floor heating is a low heat system laid underneath flooring and provides an even heat throughout the property without dust, noise, air movement, dehydration or overheating.
In terms of supporting a building that has been constructed with the principles of a Passive House, a hydronic heating system, which can be powered using a variety of energy sources including natural gas boilers, electric heat pumps, geothermal heat pumps, wood-fired stoves and solar hot water systems, can prove fitting for a Passive House.
Download this white paper to find out why it is necessary to re-evaluate our approach to heating in Australian buildings.