Overview
This lecture discusses how design decisions affect energy and environmental impacts, emphasizing the importance of setting specific, measurable goals to improve building performance.
Impact of Design Decisions
- Every product choice, like using disposable vs. reusable cups, has energy and environmental impacts throughout its lifecycle.
- Building design decisions are significant as buildings last for decades and affect energy use and environmental outcomes for years.
- Choices affect not only the use phase but also material production and end-of-life disposal.
Importance of Measurable Goals
- "Green building" is vague unless clearly defined and measured.
- The LEED rating system was developed to quantify and compare building sustainability using a points-based system.
- Measurable criteria ensure clarity in goals and facilitate meaningful progress.
Setting and Achieving Energy Goals
- Relative energy goals compare building performance to benchmarks, e.g., using 30% less energy than a baseline code like ASHRAE 90.1.
- Absolute energy goals, such as using less than 25,000 BTUs per square foot annually, are clearer and easier to measure.
- Zero Energy Buildings use no more energy than what is generated onsite by renewables, providing a concrete, annual target.
- Zero Energy Ready Buildings are efficient enough for future onsite renewables to meet their energy use, even if they do not yet have renewables.
Defining Energy Targets
- Energy Use Intensity (EUI) targets vary by climate zone and are summarized in guides such as the Advanced Energy Design Guide.
- High-rise buildings may need to procure renewable energy off-site to meet zero energy goals.
- Achieving zero energy ready typically requires a 40–60% reduction from conventional energy codes.
Key Terms & Definitions
- LEED (Leadership in Energy and Environmental Design) — A rating system that measures building sustainability through points.
- ASHRAE 90.1 — A standard providing minimum energy efficiency requirements for buildings.
- Baseline Measurement — The reference energy use level against which improvements are evaluated.
- Energy Use Intensity (EUI) — Annual energy use per square foot of building area.
- Zero Energy Building — A building that generates at least as much energy on-site as it consumes annually.
- Zero Energy Ready Building — An efficient building capable of being powered by on-site renewables in the future.
Action Items / Next Steps
- Review the additional resources page for more detailed information.
- Consider how to define and measure sustainability goals for your own design projects.