Sustainable Design from ARE exam isn’t just about “being green”— it’s about understanding how life cycle assessments, rating systems and enforceable code integrate into a real-world building design process. Here is the breakdown from its concept to industry standards.
What is sustainability?
It is the ability to meet the needs of the present generation without compromising those of future generations.
What is sustainable design practice?
Sustainable design practice focuses on reducing environmental impact, conserving resources, and enhancing human well-being throughout the lifecycle of a product, system, or service.
Why does sustainable design practice matter?
It matters because it represents a mentality shift from short-term, purely functional design to a holistic approach that considers long-term impacts on the planet and society. Through its holistic approach, it will ensure long-term environmental, social, and economic benefits.
What are the strategies to reach a project's sustainability goal?
Common strategies for existing buildings are through recycling, reuse, and also mitigating hazardous materials.
Adaptive Reuse: It is to repurpose existing buildings for new uses. Though it might not always be the most cost-saving solution, it is often the greenest option because it reduces resource consumption, cutting emissions and delivering resilient solutions.
Recycling Materials: It is the capacity of a previously used material as a resource in the manufacture of a new product. It directly meets sustainability targets because it aligns with the circular economy and the waste hierarchy, which prioritize reuse and recycling over landfilling.
Hazardous Material Mitigation: It is a proactive way to reduce the use of harmful substances that pose risks to human health and the environment; thus, it directly meets the purpose of sustainability by reducing environmental impacts.
Common strategies for new constructions are using energy-efficient design principles, such as conducting Life Cycle Cost Analysis or planning for certifications during the early phase of a project, which you will dive more in-depth into in the following paragraph.
What does energy efficiency mean?
Energy efficiency is the reduction of the energy that must be consumed to provide various services and functions, particularly compared to sustainable standard baselines.
How do we evaluate energy efficiency?
There are several methods, tools, or certifications that we use for evaluating the environmental impact. Here are some common examples:
Life Cycle Assessment (LCA): It is a systematic method for measuring the total environmental impact of a product across its entire life. There are four stages covered in the assessment, from raw material acquisition, manufacturing, use and maintenance, to the product's disposal.
Whole Building Life Cycle Assessments (WBLCA): It is a systematic method for analyzing all inputs, outputs, and potential environmental impacts of a building over its entire life span. Unlike product-level LCA, which focuses on individual materials or components, WBLCA considers the entire building as a system, providing a holistic view of embodied carbon, resource use, and environmental impacts.
Environmental Product Declarations (EPD): It is a verified standardized document that communicates the life cycle environmental impacts of a product. This tool is developed by manufacturers who follow ISO 14025 standards to provide objective, third-party verified information about their products.
EPDs can be used along with other product certification systems, such as GREENGUARD for flooring, Forest Stewardship Council (FSC) for wood products, GREENSEAL for doors and windows, etc.
LEED: It stands for Leadership in Energy & Environmental Design. It is a green building rating system that is designed to provide an actionable framework for designing, constructing, operating, and maintaining energy-efficient and sustainable green buildings. Its credits surround these areas: Decarbonization (50%), Quality of Life (25%), and Ecological conservation and restoration(25%). There are four certification levels to be achieved within LEED: Certified(40-49), Silver(50-59), Gold(60-79), and Platinum (80+)
Green Globes: It is also a green building rating system. Unlike LEED, Green Globes are especially applied to commercial real estate. Buildings are scored out of 1000 points. Unlike most LEED credits, which have prerequisites, projects submitted to Green Globes are allowed to remove points altogether to prevent projects from being unfairly penalized for environmental criteria that are physically impossible to meet. When points are removed, a project's target threshold shifts to a customized scale. The evaluated building must achieve at least 35% of the adjusted points pool to earn the certification.
What are the regulations and industry standards related to sustainability?
There are many standards related to sustainability. I just highlight a few of the most well-known and popularly adopted, such as:
ASHRAE 90.1- Energy Standard for Buildings Except Low-Rise Residential Buildings. It is a widely recognized energy efficiency standard that sets minimum requirements for the design and operation of commercial buildings. It outlines building envelope requirements, zone isolation, insulation for floors/ceilings/roofs, and power allowance calculations.
ASHRAE 189.1- Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings. It establishes mandatory, prescriptive, and performance-based requirements. Unlike LEED guidelines, ASHRAE 189.1 is code-enforceable, making it suitable for adoption by local, state, and national jurisdictions.
ASHRAE 700- National Green Building Standards. It provides sustainable standards for residential buildings. It uses IECC as a basis and applies to residential buildings.
ASHRAE 62.1- Ventilation and Acceptable Indoor Air Quality. It establishes...
minimum ventilation rates for a wide range of occupancy types. requirements for HVAC system design, outdoor air quality assessment, infiltration and air distribution.
operational and maintenance practices to maintain acceptable IAQ.
limits on contaminants and guidance on moisture and biological growth controls.
ASHRAE 62.2- Ventilation for Acceptable Indoor Air Quality in Residential Buildings. This standard established the following standards:
minimum demand-controlled ventilation rate based on floor area and occupancy number.
local mechanical exhaust system for kitchen and bathroom
filtration requirement for air-cleaning devices
moisture control
Optimal IAQ procedure.
ASHRAE 55- Thermal Environmental Conditions for Human Occupancy. It establishes ranges of indoor environmental conditions to achieve acceptable thermal comfort for occupants. It is directly linked to sustainable design practice because it provides the scientific basis for creating a comfortable, healthy indoor environment that can be achieved with efficient systems.
IECC- The International Energy Conservation Code. It is a model code developed by the International Code Council to regulate minimum energy conservation requirements for new buildings.
IgCC- It stands for the International Green Construction Code. It is a comprehensive green building code developed by ICC in collaboration with other industry organizations. Unlike LEED, the IgCC establishes mandatory. enforceable requirements that jurisdictions can adopt to ensure buildings meet minimum sustainability standards.
The IECC focuses strictly on energy efficiency and savings for buildings. In contrast, the IgCC is a broad, whole-system green building code that covers energy alongside site sustainability, water use, indoor air quality, and materials.