BASIX #7: Balancing Low Carbon Materials and Operational Technologies

Balancing Priorities: Low Carbon Construction Materials vs. Operational Footprint Technologies for New Homes

In the face of climate change challenges, the construction industry is increasingly committed to reducing the carbon footprint of newly built homes. This pursuit can involve making crucial decisions regarding budget allocation between low-carbon construction materials and technologies that minimise the ongoing operational footprint of the home, such as solar and battery configurations.

In this article, we will explore the reduction of carbon emissions throughout the lifespan of a typical home. We will delve into the trade-offs associated with different approaches and provide valuable considerations to guide homeowners, builders, and architects in achieving optimal results within their respective budgets.

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Low Carbon Construction Materials:

Opting for low-carbon construction materials*, such as recycled or locally sourced materials, presents a significant opportunity to reduce the embodied carbon of a new home. These materials require less energy during production and transportation, thereby minimising greenhouse gas emissions. By incorporating sustainable building practices like efficient insulation, passive design, and responsible waste management, the ongoing energy usage of the home can also be enhanced. It is worth noting that these operational outcomes can also be achieved using materials with higher embodied carbon, such as bricks and cement. However, it is important to acknowledge that low-carbon materials may come with a higher upfront cost compared to conventional alternatives. Balancing the initial construction budget while aiming for lower embodied carbon requires significant collaborative efforts between architects, builders, energy specialists and suppliers. Currently, due to the economies of scale and the specialised nature of designing and building with these materials, higher upfront costs are more likely.

Operational Footprint Technologies:

Investing in technologies that reduce the ongoing operational footprint of a home, such as solar and battery configurations, offers long-term benefits in terms of energy efficiency and carbon reduction. Solar panels harness renewable energy, reducing reliance on fossil fuel-based electricity and minimising greenhouse gas emissions. Coupled with energy storage systems, like batteries, homeowners can maximise their energy independence and resilience while minimising their environmental impact. While operational footprint technologies offer significant environmental advantages over the life of a home, they do require upfront investment. The cost of solar panels, batteries, and associated equipment must be factored into the overall project budget. However, it is important to note that many of these technologies are now widely available, benefit from economies of scale, and continually improve in efficiency over time. Additionally, government incentives and energy cost savings make these technologies increasingly attractive options.

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Finding the Balance:

For the sake of simplicity, let's assume that both low and high-carbon materials result in a Nathers 7-star home, which will be the minimum requirement from October 1 this year. Consequently, ongoing energy usage will be relatively similar in both cases. If budget allows and the goal is to reduce carbon emissions across the construction and lifespan of the home, it is ideal to utilise both low embodied carbon materials and invest in technologies that minimise the ongoing carbon footprint.

However, striking a balance between low-carbon construction materials and operational footprint technologies while constrained by budget is a complex task that requires a holistic perspective. Here are some considerations to guide decision-making:

Let's take a closer look at the carbon footprint and potential solutions for a typical home built by our company, spanning around 350-400m^2 and designed to accommodate a family of 4-5. On average, the construction of such a home results in approximately 70-90 tonnes** of embodied carbon. If this family is a high consumer of electricity and, perhaps, has a pool, their ongoing annual carbon emissions would amount to 8-9 tonnes*** assuming all the power used comes from non-renewable sources.

Now, imagine we could either implement materials that reduce the embodied carbon of the home by 50% or instead implement a solar/battery system that provides the ongoing energy requirement separate from the grid.

If we were to pursue only one approach, either low carbon materials or using solar and battery systems to power the home, both options would result in comparable overall impacts to the whole of life carbon footprint in less than 5 years. However, the significant advantage of the solar and battery option lies in the potential for substantial, if not complete, elimination of energy costs for the homeowner over this period, effectively offsetting the original investment.

Moreover, there are additional possibilities to consider. For instance, you could choose to over specify the solar system, enabling the surplus energy generated to be fed back into the grid. Over time, this would help offset the embodied carbon in the home. Alternatively, at the completion of construction, you could opt to pay for carbon offsets, which typically amount to around $2000**** to fully offset for the example provided.

In most cases, budget will be the limiting factor but by implementing a mix of these strategies, we can create a more sustainable and environmentally friendly home, reducing or offsetting both embodied carbon and ongoing energy costs. It's an exciting opportunity to embrace renewable technologies, achieve financial savings, and contribute to a greener future.

To learn more about how Hall & Hart can help you offset the Carbon in your new home please click here

* https://www.buildersforclimateaction.org/report---nelson-material-carbon-emissions-guide.html

** https://www.buildersforclimateaction.org/report---embarc-report.html

*** Based on using calculator at https://www.carbonhalo.com/personal/

**** based on approx. $20 per tonne https://www.carbonhalo.com/

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