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Passive house principles

Passive house institure 2024


Passive house is an internationally recognised, performance-based energy standard in construction, aimed at reducing a buildings energy consumption whilst improving the health and comfort outcomes for occupants and the longterm durability of your home.  Passive house certification, as an extra step, provides a rigorous, independent assessment to then ensure these design principles have been implemented successfully on paper and later on-site. 

The five principles of the Passive house standard are:

  • Airtightness

  • Thermal insulation

  • Mechanical ventilation heat recovery

  • High performance windows

  • Thermal bridge free construction

When implemented correctly, the Passive house criteria is achieved:

  • Thermal comfort - Indoor air temperature of between 20-25 deg

  • Heating and cooling demand - 15kWh/m2/yr or load of 10W/m2  (reduced energy consumption and cheaper energy bills)

  • Humidity levels - approximately 60% relative humidity at 25°C

  • Airtightness - Maximum reading of 0.6 ACH50 with on-site verification

  • Energy demand - Maximum Primary Energy Renewable (PER) demand of 60kWh annually per square metre of living space

In our practice at Ertha Design, we have made Passive House the backbone of our design philosophy, applying these principles to all our designs, with or without certification and within the confines of budget.  It is our goal to inform and guide our clients where we can to enable you to reap the benefits of building better for health, comfort and also the longevity of your home.  


Passive solar design goes hand in hand with passive house, considering orientation, thermal mass, insulation and glazing size to work together to take advantage of natural sources of heating and cooling, such as solar access and cross-flow ventilation.

Not all sites or climate zones lend themselves to optimal levels of human comfort all year round.  So whilst we love to harness the natural energies that mother nature has on offer,  unlike passive solar design, Passive house design does not rely on having optimal solar orientation, thermal mass and cross ventilation to achieve high levels of comfort and energy efficiency, making it the perfect choice for sites that don't have a desirable northerly aspect.



There is a synergistic interplay between planetary and personal well being with our natural and built environments shaping us as individuals just as we too can shape and influence our natural and built environments.  Humans have a long history of modifying the environment to suit our own needs, much at the sacrifice of other species, ecosystems and our own spiritual connection.   


To reverse decades of over consumption and degradation, we should look beyond the built form and consider the site, the flora and fauna as one complete entity that co-evolves and thrives in unison.  We take a boundary to boundary approach, exploring opportunities on your site to restore local ecosystems through mindful landscaping.  Healthy ecosystems help to protect people, optimise living conditions and safeguard a stable and biodiverse future.   


Our influence as individuals has the collective power to generate positive change in our communities, and this starts at our own front door.   At Ertha design, we are inspired by natures beauty, self preservation and balance, designing spaces that mutually respect and foster a deeper connection with nature, restoring tranquillity and purpose.  

LUXURY, with a conscience...

Permanence and timeless appeal inspires us to protect and preserve that which is of high value to both us and future generations, safeguarding a site's carbon footprint over time.  

A project which brings with it a healthy budget can translate into a well considered, well executed home, curated to the highest of standards that Ertha design strives to produce.

​Our process can be as rigorous and tailored to meet your needs as you like.  You can either become heavily involved in the creative process or take a back seat while we unearth the intricacies and creative potential of your project...

Luxury home


We take a multi-disciplined approach to design, tying together our learnings from the ever evolving building sciences, Passive house technologies, as well as other sectors such as health & building biology, biophilic design and environmental conservation...  The whole is greater than the sum of its parts...


Our home is our sanctuary and our integrated approach is aimed at supporting you and your family to live well whilst strengthening your local environment and community.


The exponential impact of collaboration and a shared vision is key to the success of any project.   This begins with you and your architect, but extends to your whole project team and supplier network.  We work with you to form a team that is highly supportive, collaborative and passionate about shaping a brighter future.  

Ertha Design are committed to providing a customised and collaborative design experience to explore how far we can push the envelope for you... we'll listen, inspire and work closely together to create your story...  big or small.

connection with nature
aging in place


Our designs, choice of materials and construction processes need to promote long-term durability and resilience against mother nature, whether it be fire, flood, cyclone or drought... or simply, to require less ongoing maintenance and repair. 


A sustainable structure is built with longevity in mind, choosing products which ideally have a long lifespan of ideally 50-100 years.   The more often a building element needs repair or replacement increases the overall resource use and carbon footprint of that home.  Elements which cannot be made to withstand long periods of occupancy should be selected based upon their environmental credentials and ability to be recycled or repurposed.  


Universal design aims to make spaces more accessible, regardless of age, disability or other factors.  Recent changes in the building code have now recognised the importance of providing flexible and equitable access to our buildings, enabling aging in place and more opportunity for inter-generational care.


Trends come and go, as do people.  Whilst every home is unique and personalised,  ideally it will have widespread appeal and be flexible enough to meet the changing needs of different people at different times throughout a buildings lifespan.

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