I'm glad you asked! That's what this section is all about.
Click on the side bar topics to get some background on the carbon footprint of the construction industry, and the average Australian home, or just read on.
Let's start with the big picture.
Global Carbon Dioxide emission are currently at 36 billion tonnes annually and climbing, as can be seen in the graph of emissions since the start of the Industrial Revolution in the 1800's.
How much of that 36 billion tonnes is related to buildings?
The answer is a surprisingly high 39%. This figure made up of both operational carbon, and the emissions related to the creation of the building materials.
So a big part of climate change can be laid at the feet of the building sector, and the human desire to build. This large percentage means that it is true to say there is no getting to Net Zero without the building industry onboard!
But don't be discouraged by these large numbers.
It means that if you are in the building industry, you have a big part to play in making that change happen. Your choices count. How you run your business counts. What you build makes a big difference!
And it is possible to build Net Zero Carbon Homes, cost effectively, TODAY.
Commonly when people talk about a Net Zero Home they are just talking about the energy it uses over the year - known as Operational Net Zero. That is, a house that through the solar PV on it's roof and low energy needs, produces as much power annually as it uses.
And if that house is all-electric, the amount of fossil-fuel-derived electricity used by the home over the year, will be equal to the renewable electric energy produced by the home and fed back into the grid, to be used by others.
In that sense, over a year, such homes have a Net Zero energy and carbon balance.
But houses are also full of Embodied Carbon. That is, the CO2 given off by the energy used in creating the materials the home is made from.
A house that minimises it's embodied carbon through careful material selection and then puts on enough solar panels to not only offset it's energy use, but also to pay back its embodied carbon 'debt', or offsets that debt, can be said to be a True Net Zero home.
Both Operational Net Zero and True Net Zero outcomes for our homes are possible today, with current technology. How to put it all together is what the 5 Steps in the Net Zero Roadmap is all about...
Here is the pie graph of the Average Australian Home Energy Use. You will be seeing this on and off throughout the Roadmap to show expected energy savings in each wedge from various strategies.
The pie graph shows how the energy gets split into the various functions of the house, and represents an average of new and existing homes across all states.
To provide the energy for the functions in each wedge, fossils fuels are currently the dominant energy source with some states & territories being more carbon intense, and others less so.
(Big tick to Tassie with its very low electricity grid carbon intensity due to hydro power!)
On average however, each Australian home is responsible for almost 6 tonnes of CO2 being generated each year in the burning of those fossil fuels.
(And nearly 8 tonnes average currently in Victoria. Come on Vic!)
An average home lasts at least 50 years (a conservative estimation). If nothing changed in the carbon intensity of our grids (which it must), that would mean an incredible 300 Tonnes of Operational CO2 would be released over the life of the house!
While we do expect this figure to drop off significantly for all-electric homes as the grid greens over the next 20 years1, this is still a disgraceful amount of pollution.
But it doesn't have to be that way anymore. And we don't need to wait for the grid to green.
We now have the know-how, the technology, and the price points are right, to get rid of this carbon load completely - today. And the Roadmap will show you how.
(As an aside, Residential buildings are responsible for around 24% of overall electricity use in Australia2, and with almost 200,000 Class 1 dwellings being added each year, if the aim is for an affordable decarbonised grid, a lower energy demand from new homes is a must.)
1 As renewable energy production replaces fossil fuel plants, the carbon intensity of all-electric homes will come down. Gas powered homes on the other hand will remain at the same intensity. The gas industry has mentioned mixing in 10-15% green hydrogen, but this approach is unlikley to be cost effective and is not the scale of reduction required.
2 Australian Govt, Improving_the_energy_and_emissions_performance_of_buildings_-_factsheet.pdf
The other source of carbon in our homes, and a harder nut to crack, is embodied carbon. Embodied Carbon, refers to how much CO2 is released during the creation of the materials we make our homes out of.
And how much CO2 is embodied in the average house?
Tying down an average has not proved easy. There have been a number of studies over the years with a wide range of answers. The variation has been due largely to differences in research approach, and what gets included.
Some studies only include the carbon embodied in the products from creation to the point of leaving the factory gate. Others include the transport and construction energy too. And others look at the full life cycle, including maintenance energy, and end of life considerations.
A new publication, “Race to Net Zero”, looked at a number of international & Australian studies, and adjusted them all for the same assumptions; from resource extraction to building handover. The graph below shows their findings:
If you average of all the studies the answer is 1.27 Tonnes CO2 / m2!
But as you can see there is a fair bit of variation.
So, as a rough Rule of Thumb, you can assume at least 1T+ of carbon dioxide has been released for every square meter of the standard new home.
And with the average house being 200m2+, that's at least 200T of CO2 already embodied in the structure at handover!
Easy to remember, and depressingly large. In fact, that's heavier in a polluting greenhouse gas, than the weight of the average home itself!
But, again, don't be discouraged. Step 5 of the Roadmap (Energy Generation & Offsetting) will show how we can make a significant impact on this all-too-large figure too, through a range of simple strategies.
Now we have some figures it is easy enough to work out the total carbon intensity of the average Australian home.
300T CO2 for 50 years of operation if nothing changes in carbon intensity of our power supply.
Plus, 200T CO2 embodied in the average house Gives a whopping 500T!!
That's over twice the weight of the average home! And frankly it is disgraceful.
But again we have good news...
We can turn this around today.
You can do it on your next project.
All it takes is a little education, and the 5 Steps in the Roadmap to Carbon Zero Homes.
So where is the building industry headed?
The good news is all signs point to Zero.
Nationally the recent Climate Bill commits Australia to a 43% energy reduction by 2030, on the way to economy wide Net Zero by 2050. State governments are also all locking in targets.
For the building industry, the signs are also clear.
The Trajectory for Low Energy Buildings, signed off by state Energy Minisiters and followed by the Australia Building Codes Board, requires all buildings to be Net Zero Ready by 2030. That is, all new buildings must have an efficient thermal shell, and efficient fixed appliances, such that if PV (solar panels) were put on the roof, they would be Net Zero.
And that’s by the end of the decade.
More recently, 7 star and Whole of Home requirements have been brought into the 2022 National Construction Code (NCC) to create a mechanism to measure and regulate new home energy use.
What does this all mean?
It means the tide is only going in one direction, and those builders and designers who don’t embrace the change will be left behind.
But don’t worry.
This site aims to make sure you have everything you need to know to bring increasingly energy savvy consumers a new efficient, modern, Net Zero product.
Apart from saving hundreds of tonnes of CO2, here are some further benefits of a Net Zero home.
FOR THE HOME-OWNER
Comfort & Quality:
7 star + passive solar design, high performance construction, and detailed insulation, ensures more stable internal temperatures for maximum comfort year round, and greater resilience to temperature extremes.
Detailed insulation means quieter homes, (especially where double glazing is chosen), to create a quiet place of sanctuary from the outside.
Low Home Energy Bills:
A Net Zero house produces as much power over the year as it uses.
This means huge savings on power charges and protection from bill shock, leaving owners money in their pocket to spend on what matters .
Peace of Mind:
Consumers want beautiful homes, that don't destroy the environment. 'Nuff said.
FOR THE BUILDER
This is a new market that is developing, along with a desirable product. Like any market early entry is an advantage. It makes business sense to get on board early and ride the green wave.
Word of Mouth marketing:
All else being equal Net Zero homes are just better. Which means it is natural for Owners to talk glowingly about their homes, and, if you do a good job during the build, about their builder!
You can look in the mirror and know you are producing something you can be truly proud of. A home that leads to a bright future for all of us. It's a good feeling.
FOR THE COUNTRY
A Net Zero Australia by 2050 requires electrification of everything that can be electrified onto an almost carbon free grid powered by renewables and supported with distributed batteries and smarts for regional demand management.
This is all doable, but the cost of the infrastructure depends on the draw required. If we do nothing to reduce current energy demand from housing it will cost a bomb. If our homes are efficient and mostly look after themselves, the cost to society will be much lower.
AND OF COURSE, FOR THE ENVIRONMENT
In Australia each year, there are around 200,000 new residences being built, so it goes without saying, the carbon savings from Net Zero, low embodied carbon homes to the environment are massive!