Little Pot of Gold
PROJECT NAME
LITTLE POT OF GOLD:
Are we reaching for the stars or are we chasing rainbows?
What are your net Design Matters National emissions score 2023 to 2050 (Tonnes)
Of the 24 versions, the best emissions score is negative 563 tonnes by 2050 (Low Carbon - Perth), the worse score is negative 248 tonnes by 2050 ("Chasing Rainbows" - Brisbane)
What is your cost estimate of the project?
What if any cost factors influenced the ESD decisions?
The design intent from the outset was to focus on a compact form factor, and space-efficient floor plan to have a smaller environmental footprint. The focus was then to prioritise the quality of a smaller building envelope, instead of a large quantity of floor area.
Construction Cost and affordability is always a high priority. This competition submission provides data for the same house design, (with 4 options of how to construct it, in each state's capital city), with a total of 24 options.
Building costs vary across the country, and due to the differences in the building envelope (to achieve low operational energy, and low embodied energy in these different locations), the costs vary. The data shows the most cost-effective option is located in Brisbane (~$720K), with the most expensive option located in Hobart (~$970K).
The competition criteria stated what we believe to be an unrealistic budget of $700K (due to current construction costs) and although the data shows this budget was almost possible, it illustrates that this is not a "one size fits all" approach to home-building.
See our appendix for our the full methodology for our cost analysis.
These were calculated based on a Quantity Surveyor's review of our design data and illustrate that building new houses is expensive, and therefore for such a substantial investment we wanted to show that it is important that consumers understand they are getting what they are paying for! The elements that drive thermal performance are only ~25% of the overall cost.
Prioritisation is key!
Please explain what considerations, design principles and rationales have informed your design.
The aim was to design a modest 3-bedroom multi-generational home that could be buillt in any of the state's capital cities. The focus is on quality not quantity. We wanted to prove that we could design a desirable comfortable net-zero home, regardless of location across Australia.
We wanted to ensure that we could not only meet the competition criteria, but exceed expectations by going a step further to provide a truly comfortable home that is healthy for the occupants and healthy for the planet.
All the designs meet the criteria of the International Passivhaus Standard, with options for Low, Medium, High Embodied Carbon construction-material options. There is also a fourth option "Chasing Rainbows" which has more thermal mass and higher embodied carbon, and although it achieves a higher star rating... it takes a lot longer to achieve net-zero carbon, and the gap between 'designed performance' and 'as-built performance' is known to be vast....
An understanding of the local bio-climatic conditions was a starting point, then Passive Solar Design principles were integral to ensuring winter sun could enter the home, and summer sun could be excluded (both by the eaves, and with external operable shading devices for the trickier times of the day/year - particularly for times like the Autumn equinox which can often still be hot afternoon sun!).
Smart design choices about the extent of the window-floor area ratio means we could optimise the heat loss/gain. Excellent insulation to roof, walls and floor, with a well-sealed thermal envelope means the house is not leaky. A controlled ventilation strategy with the implementation of a heat-recovery mechanical ventilation system (with de-humidificaiton in some locations) ensures minimal heat is lost during winter (or coolth in summer) and provides a constant supply of filtered fresh air.
What energy rating did you achieve?
The NatHERS ratings for all of the 24 designs are found on the website and range from 7.0 star minimum (Mid- Perth) to maximum 10 stars ("Chasing Rainbows" - Brisbane) based on the FirstRate Energy Rating tool.
All of our designs (excluding the "Chasing Rainbows" designs) achieve Certified Passivhaus Standard using the PHPP (Passive House Planning Package Thermal modelling).
The NatHERS Energy-Rating is meant to be about the thermal comfort of the home, with allowable megajoules amounts of heating/cooling load which vary greatly for different locations across the country, and based on internal temperatures that can be as low as 15 degrees in habitable/conditioned spaces, with no heating to bathrooms/laundries/etc.
The PHPP on the other end requires stable temperatures of 20-25 degrees for the whole house, with humidification control, all year round - meeting the guidelines of the World Health Organisation.
How sustainable do you judge your design solution to be?
These designs are exemplar in their sustainability credentials - keeping the building footprint modest in size, and the environmental footprint modest in energy consumption. The data illustrates that our designs (all 24 of them) meet the definition of 'True Net Zero'.
For humanity to thrive in the future, we need healthy homes and a healthy planet. The "Little Pot of Gold" design meets its intentions of being environmentally sustainable, socially sustainable, economically sustainable, and spiritually sustainable (considering planet, people, profit and purpose). See our story "True Net Zero - a fairytale?" to understand more.
However it is also worth noting that 'Sustainability' is often just about doing "less bad" but for a truly regenerative approach to a thriving, living future we also need to consider doing "more good".
This is our intention - to look more holistically to respect each unique site, considering biophilia and beauty, harvesting rain water to be self-sufficient, a garden design that includes a pond and endemic native plants to improve bio-diversity and respect the local ecology, use of non-toxic construction materials, a focus on a healthy indoor environment, and ensuring the front garden provides a connection to the street to encourage community engagement, and for the home-design to be a true example of what is not only possible - but necessary - to be responsible and responsive to the climate-emergency.
How have you arrived at the choices of materials included in your design?
The aim was to illustrate that it is a simple and smart choice to use eco bio-based natural materials (locally-sourced timber, straw, hemp) to achieve the desired outcomes for the building's thermal envelope.
Embodied Carbon calculating is a complex and arbitrary process, and for residential homes we wanted the message to be simple. As structural-steel and concrete have very high embodied carbon, we purposely chose to exclude these from our low embodied-carbon designs.
The "Chasing Rainbows" designs achieved high star ratings due to using concrete as thermal mass - however we have proven this is not necessary to obtain the desired outcomes of low operational-energy and low embodied-energy.
We focused on the external thermal envelope (floor, walls and roof) for the purposes of these calculations as this is what is having the most impact. Everything else inside the house (floor coverings, wall/ceiling linings, fit-out, fittings and fixtures) is assumed to be the same and will vary due to owner choice.
Continued education of consumers is vital to their understanding of the impact of their choices (often which designers have much less control over). Designers do have control over the structural enclosure (the thermal envelope) and this is where we've focused out attention as this is where we have a responsibility to make the most ethical choices possible.
Please describe how the elements of your design will allow families, lifestyle and life stages to thrive and evolve over time.
Our intention was for this to be a modest house of 120sqm - that still could have three bedrooms plus study, two bathrooms*, with indoor and outdoor living areas. This could accommodate multi-generations and we wanted the flexibility of the rooms and spaces to be universally-accessible.
The house meets the Liveable Housing guidelines with an accessible bathroom and allowance for ramped access (for our timber-framed floor options).
The second bathroom is a shower-room as part of the laundry with a separate loo to allow occupants to utilise these spaces at the same time. Built-in window seats in bedrooms allow for cosy nooks to relax and enjoy the winter sunshine. The built-in seat to the dining area (with incorporated storage) helps connect occupants to the view of the back garden whilst being an efficient use of space. The open-plan kitchen/living/dining is a good size with a good connection to backyard. Raised raked ceilings to the living area and bedrooms create a sense of spaciousness.
What will it be like living in this house?
This house will be the envy of the neighbourhood! It will be a joy to the occupants because it functions and performs as intended! Simple, honest, ethical and beautiful.
And cheap to run too! Less bills, more bliss!
We believe Australians deserve to live in homes like the "Little Pot of Gold" - and according to this story they have good reason to want one!
Tell us why will this be the ‘must have’ dwelling that people will want to live in now and in the future?
Comfortable, healthy, beautiful; what more do you need?
It is well known that much of our existing housing stock has similar indoor comfort levels to 'wooden tents'. It is widely agreed our homes need to be more efficient, more comfortable, more healthy and more resilient.
Although the star-rating system is well-intentioned, the outcomes are not predictable and there can be negative consequences if the building-science is ignored. The knowledge and wisdom is available to us, and there is a better approach.
In a warming climate, a leaky (10+ACH50), thermally-heavy, high-rating NatHERS home may resemble a similar construction methodology to a pizza oven. One of these high perfomance, highly resilient , low carbon (all senses) homes will be a life saver; possibly quite literally!
What will drive consumer demand for this kind of dwelling?
A focus on health.
Knowledge that there are smarter choices available.
The realisation that saving money is worthless when your family's health is at stake.