A recent report from the United Nations reveals that in 2021, building construction and operation were responsible for 37% of carbon emissions related to energy and processes. While this sector contributes 25% to overall human-caused greenhouse gas emissions, it still represents a significant quarter of the total emissions driving planetary warming.
Decarbonizing the built environment is imperative, and fortunately, we have the knowledge to transition to a low- or zero-carbon future. This transformation will require considerable time and substantial investments amounting to trillions of dollars, but it’s a challenge we’re capable of tackling.
Approaching Design Sustainably
McKinsey & Company, a leading global management consulting firm, conducted a comprehensive analysis on building decarbonization, highlighting a crucial insight: most decisions affecting a project’s greenhouse gas emissions are made before construction even begins. For stakeholders aiming for minimal carbon impact, strategic design choices are paramount. The most effective time to steer a building towards sustainability is during the initial design phase.
In the United States, builders often adhere to LEED standards for selecting materials and designing systems, sometimes incorporating Passive House principles as well. These standards complement each other, with LEED offering a broader perspective and Passive House emphasizing energy conservation.
However, these standards aren’t exhaustive. There’s a growing trend in mainstream construction towards incorporating innovative elements like reflective or green roofs to reduce cooling loads during the day.
Transitioning Building Heating & Cooling
According to McKinsey, operational activities such as heating and cooling contribute to 69% of total building emissions. Switching to lower-carbon fuels or higher efficiency equipment is frequently the most impactful step builders and owners can take to reduce carbon emissions.
In existing buildings, fuel-switching requires substantial initial investments and may pose logistical challenges. While upgrading from an old oil boiler to a natural gas one can decrease carbon emissions and eventually pay for itself, this payoff typically takes years. Transitioning from oil or gas to efficient electrified heating, often involving heat pump installation, offers even greater decarbonization benefits. However, upfront costs, especially if infrastructure upgrades are required, can be prohibitive.
It’s crucial for building owners to prioritize investment in lower-carbon HVAC systems while being realistic about associated costs.
Addressing “Boring” but Impactful Changes
While switching major appliances to lower-carbon options yields significant carbon reductions in existing buildings, even seemingly mundane changes can make a difference.
Improving insulation represents the simplest and most effective change in this regard. Upgrading a building from “low insulation” to “medium insulation” standards, according to McKinsey, can reduce energy demand by up to 20%, typically paying for itself over time.
Tackling Material Challenges
Materials contribute about 28% of overall building and construction emissions, with steel and cement being the primary culprits due to their carbon-intensive manufacturing processes.
Increasing the life expectancy of building assemblies represents a straightforward approach to mitigating emissions. Roofing systems, for example, can last 40–50 years, but often fall short due to poor construction quality or subpar materials. By adopting durable construction practices, the carbon footprint of buildings can be significantly reduced.
While carbon-neutral cement production and steelmaking are still years away from cost competitiveness with traditional methods, builders can currently reduce embodied emissions by using lower-carbon recycled steel and concrete and integrating lower-carbon structural materials like mass timber where feasible.
Embracing Innovation and Quality Assurance
The construction industry has traditionally been cautious about adopting new technologies and materials, prioritizing proven longevity and reliability. Implementing third-party quality control and testing during construction can prevent premature failures and enhance the longevity of construction assemblies.
While the construction industry’s risk aversion is understandable given the long-term nature of its projects, a shift towards prioritizing quality assurance and longevity is necessary for achieving decarbonization goals. This transition will take time, but it’s imperative that building owners and contractors invest in longer-lasting construction practices to effectively reduce carbon emissions. In conclusion, while the construction industry faces significant challenges in decarbonizing, a concerted effort towards sustainable design, transitioning to lower-carbon heating and cooling systems, implementing effective insulation measures, and prioritizing durable construction practices can pave the way towards a greener future.