Tag Archives: passive solar design

The Role of Thermal Inertia: With Passive Solar Design of Buildings

A refresh of ‘solid thinking’ by Adj Professor Garry Baverstock AM, B Arch, MSC, LFAIA, February, 2020

A big distraction in the past decade has been the argument put forward by some researchers that somehow heavy weight materials are part of the problem with dealing with Climate Change. With Passive Solar Buildings this is simply not the case. Affordability and Viability of course need to be considered but there is still a strong case for quality buildings to incorporate thermal mass materials.

Picture of SEIC building 1993 winner of the National Energy Award

Simplistic Arguments

The simplistic reports by some researchers, and of course the framed and lightweight building industries lobbyists, over exaggerate the role of embodied energy. We have known for over 50 years that embodied energy only accounts for 2-20% of the energy and carbon over the lifecycle of a building.  By far the odds are in favour of energy use being the main determinant of energy management strategy over the life cycle of a building.

Land Use Determinant

Not all land uses require long lasting buildings though. They also don’t require a solid capital investment because of the reasonably temporary nature proposed for the buildings and the scale of urban living in a built environment. This is where light or medium weight construction systems become more economically and environmentally attractive. Affordability is a big part of the criteria for materials selection in those cases. Lighter weight buildings are cheaper but not necessarily better. However, they do have their time and place in future sustainability. We need the best solutions for the right situation.

Solar Design Imperative

This means whether light or heavy buildings need 100% application of Solar Design. The reality is that it’s now a necessity in this era of heightened recognition of Human Impact on Climate Change (HICC), no matter what the level of thermal mass. Lighter weight buildings however can now benefit from the use of phase change chemical boards that can last up to 100 years. There are many competing but environmentally compatible approaches, even hybrid buildings. Using the correct material for the best effect is now the challenge, along with new smart technologies.

Landmark Architecture and Built to Last

However, a landmark building lasting over 50 to 100 years (in other words mainstream Architecture) is still better served by more expensive long lasting materials. Further energy reductions (30%) of energy use and consequently emissions occur when combined with Passive Solar Design strategies and thermal mass.  Use of natural and low energy means of cross, night and attic ventilation, and harvesting natural solar gains in winter, are brought together with thermal inertia to yield results.

Of course longevity of the structure, low maintenance, fireproofing, earthquake proofing, tsunami resilience, acoustic separation of rooms and the even ambience of radiative-effects in internal spaces, enhancing comfort, are all extra benefits of solid heavy weight materials.

Thermal Mass Knowledge is Still True

Why am I so sure? Have a look at the report I completed for the Minerals and Energy Research Institute (MERIWA) done in 1994. This was extracted from my research and monitoring of the Solar Energy Information Centre 1989 – 1993. The building had an optimized level of thermal mass in the building that correlated with test tunnel results at Curtin University.


The report shows the results of theoretical and practical analysis demonstrating that a passive solar building in temperate climates will save 30% pa (directly attributable to the mass) over the year on heating and cooling using thermal inertia as one of the ingredients of the passive solar strategy. This is particularly true for air-conditioned buildings. It also reduces intermittent supplementary heating and cooling to negligible amounts for non-fully air-conditioned buildings as well. This greatly offsets any extra costs and embodied energy investment in the early years of a building.

You can read the report here.

Foxcliffe Farm Ecovillage

Mike Hulme recently sent this update on the Foxcliffe land development at Witchcliffe.

Foxcliffe Farm Ecovillage

Image retrieved from http://www.nytimes.com/2008/08/24/nyregion/nyregionspecial2/24farmli.html

Dear Friends of Foxcliffe Farm Ecovillage,

I am delighted to inform you that the Augusta Margaret River Shire Council unanimously passed the amendments to the Witchcliffe Village Strategy and Local Planning Strategy that are required to enable the Foxcliffe Farm Ecovillage project to proceed to WAPC for approval.

This is the first time in two and half years, since purchasing the property, that I can write to you with some confidence that the Foxcliffe Farm Ecovillage will proceed!

The approval will enable up to 180 homes to be built on the 160acre farm. This will enable around 80% of the Foxcliffe Farm Ecovillage to be utilized for public open space, community vege gardens, dam, orchards, vineyard, recreation, community centre, backpackers/tourist accommodation, etc…

We are confident that we can achieve all of this and 100% self sufficiency in energy and water at an affordable price point of around $400,000 for house and land.

For those of you that haven’t had the opportunity to visit the Foxcliffe Farm Ecovillage it is a magnificent property with an abundance of water and great soil, immediately abutting the wonderful little town of Witchcliffe (at the intersection of Redgate Rd and Bussell Hwy, 10k’s south of Margaret River & 6k’s east of Redgate Beach).

We are hoping to receive WAPC approval by around January 2013, after which we will still have to rezone the town planning scheme (TPS), which will take us the best part of 2013. However, once we have received WAPC approval the project will have the certainty required to complete the detailed planning during 2013, so that we are ready to lodge subdivision and development applications as soon as the TPS amendment is formally gazetted.

We are very excited to be moving forward and thank the Shire’s planning officers and Council for their solid support.

We now have over 200 people who have registered interest in the Foxcliffe Farm Ecovillage; I look forward to keeping you all informed of our progress.

Kind regards,

Mike Hulme

Green Architects

Green Architects can save the client 60-90% on energy costs in their new home.


This solar movie opens the scope of solar design to commercial, institutional industrial buildings, as well as the smaller scale of residential design, including the retro-fitting of existing ones.

Prominent Green Architects Perth

A number of prominent Perth green architects are interviewed in this video together with planners who point out that well thought-out land subdivisions and master planning are crucial for the success of this strategy.

This solar movie about green architects was made in the 1990s for the Australian Institute of Architects. Dr Bill Parker was involved in the production and direction. The movie entitled ‘Green by Design’ won a government energy efficiency award in 1998.

Green Architects Discuss How to Design for Energy Efficiency

The messages on going green by design and the benefits of using green architects are still very relevant in the developed world.

to learn the basic principles and how you can best orientate and design your house for optimal comfort and energy efficiency download the Climate Sensible Designs video showing why it pays to use  green architects.  Go to the www.solar-e shop to view this and other DVDs

Solar Movies | Solar Energy + Solar Movies

Solar movies are a current internet fad but the most important solar movies are those that show you the effective and efficient way to use solar power is to build your home as a passive solar home based on your climate.

Read more about the solar movies on our website and see the link at the end of this article. In the meantime watch what Garry Baverstock A.M., award-winning green architect and solar specialist has to say:

Solar Movie | Climate Sensible Designs

In addition to our excellent building guide Low Energy Buildings in Australia and easily downloadable green home plans which are available on this website, we recommend the viewing of our solar movie‘Climate Sensible Designs – Living in a Home that Breathes’, as well as a number of past solar movie productions.

They give a clear idea of how you can empower yourself and live cheaply, comfortably and make a contribution towards saving our planet from the severity of uncontrolled Climate Change.

David Karsten, producer and presenter of several television programmes, takes you through the environmental reasons for building according to the sun.

Climate Sensible Designs is just one of our solar movies and David shows how easy it is to incorporate solar passive principles in your building design.

Once your eco-architect checks the location of your land and knows the sun’s angles for various times of the year in your area he/she will know where to place the windows, doors and shading for your new passive solar house.

Remember, it doesn’t matter whether you live in USA, Asia or Europe, the principles are still the same. Start with some research on the sun angles for your area. Once you have this information you can base the location and aspect of the house for the best passive solar results.


Eliminate Power Bills

By using the sun, wind and incoporating natural building materials you can reduce your heating and cooling bills dramatically. In some climates it is possible to completely eliminate power bills. Of course once you have a passive solar home you can choose a solar water heater and solar energy panels using photovoltaic cells, to bring your home truly into the 21st century.

Efficient water use, natural and low energy building materials, landscaping that suits the climate and local food production, will all add up to a carbon neutral or sustainable house.

Solar Movies | Passive Solar Design of Buildings

Solar Movies

The first solar movie we made is also available from our on-line shop and the information is still valid today: Passive Solar Design of Buildings.

Imagine living in a solar passive house, with solar panels on the roof to create free electricity and a solar hot water system to supply free hot water on sunny days.

Go directly to our shop to check out the Climate Sensible Designs solar movie or one of our other solar movies or read more about green building products elsewhere on this site.

Solar Movies Available Here

Should you purchase our solar movie DVD, ‘Climate Sensible Designs’,  please let us know if it helped your understanding of what can be done.