How can you use LCA and CBA to improve the environmental and economic performance of existing buildings?

1 What is LCA?

LCA is a method that quantifies the environmental impacts of a product, service, or system throughout its entire lifecycle, from raw material extraction to end-of-life disposal or recycling. LCA can measure impacts such as greenhouse gas emissions, energy use, water consumption, waste generation, and biodiversity loss. LCA can help you identify the most significant environmental hotspots in your building systems, compare different scenarios or alternatives, and communicate the environmental benefits of your actions.

2 What is CBA?

CBA is a method that compares the costs and benefits of a project, policy, or intervention from a social perspective. CBA can include both monetary and non-monetary values, such as health, safety, comfort, productivity, and social welfare. CBA can help you assess the economic feasibility and efficiency of your building projects, account for externalities and distributional effects, and prioritize the most beneficial options for your stakeholders.

3 How to use LCA and CBA for existing buildings?

LCA and CBA can be used together or separately for existing buildings, depending on your goals and resources. For example, you can use LCA to evaluate the environmental impacts of different retrofit options, such as insulation, lighting, HVAC, or renewable energy systems, and then use CBA to compare the costs and benefits of each option, taking into account factors such as energy savings, maintenance costs, occupant satisfaction, and carbon credits. Alternatively, you can use CBA to estimate the net present value or internal rate of return of your building projects, and then use LCA to assess the environmental trade-offs or co-benefits of each option.

4 What are the benefits of using LCA and CBA?

Using Life Cycle Assessment (LCA) and Cost-Benefit Analysis (CBA) can help you improve the environmental and economic performance of your existing buildings in several ways. Identify the most cost-effective and environmentally friendly solutions, avoid unintended consequences, enhance your reputation as a green and responsible facilities engineer, demonstrate compliance with environmental regulations and standards, attract more customers or tenants who value sustainability and efficiency, and contribute to global goals of reducing greenhouse gas emissions and resource consumption. These are just some of the benefits that LCA and CBA can bring.

5 What are the limitations of using LCA and CBA?

When considering the use of LCA and CBA, it is important to be aware of their limitations. Data availability and quality can be issues, particularly for older or complex building systems. Uncertainty and variability in the results may occur depending on the assumptions, parameters, and boundaries chosen. Additionally, subjectivity and bias in the valuation and weighting of costs and benefits can be present, especially for non-monetary or intangible factors. Furthermore, capturing dynamic and interactive effects such as feedback loops, rebound effects, or synergies can be difficult. Lastly, there may be conflicts or trade-offs between environmental and economic objectives, such as short-term versus long-term impacts or local versus global impacts.

6 How to overcome the limitations of using LCA and CBA?

To ensure the accuracy and credibility of your LCA and CBA results, you should follow a few tips and best practices. Gather reliable and relevant data sources, such as databases, standards, or case studies. Perform sensitivity and scenario analyses to test the robustness of your results. Utilize transparent and consistent methods, like ISO 14040 for LCA and HM Treasury Green Book for CBA. Involve stakeholders and experts to ensure the acceptability of your analysis. Additionally, use complementary tools and indicators, such as life cycle costing, environmental impact assessment, or green building rating systems.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?