LEED Indoor Environmental Quality & EPA Indoor AirPlus

Creating healthy, comfortable, and sustainable indoor environments is more important than ever as we spend a substantial portion of our lives indoors. Indoor air quality and environmental factors directly affect our well-being, productivity, and long-term health. Recognizing this, organizations like the U.S. Green Building Council (USGBC) and the Environmental Protection Agency (EPA) have developed standards like LEED Indoor Environmental Quality (IEQ) and EPA’s Indoor AirPLUS, both designed to elevate the quality and sustainability of indoor spaces.

Together, these initiatives offer a comprehensive approach to indoor environmental quality, helping to minimize the impact of pollutants, optimize ventilation, and create healthier spaces. For building owners and developers, meeting these standards isn’t just about certification—it’s about fostering environments where people can thrive.

What Is LEED Indoor Environmental Quality (IEQ)?

LEED IEQ is a key component of the Leadership in Energy and Environmental Design (LEED) certification system, which aims to create healthier, more comfortable indoor environments. Within the LEED framework, “credits” are specific standards or strategies a building can implement to earn points toward certification. Each credit addresses a particular aspect of sustainability or occupant well-being, allowing buildings to accrue points by meeting these individual requirements.

IEQ covers several credits within LEED, each targeting factors that impact indoor quality. These credits include areas like ventilation performance, which helps reduce indoor pollutants; low-emitting materials, which minimize harmful chemicals; and daylighting strategies, which introduce natural light to create a more comfortable indoor experience. By implementing these credits, buildings reduce their environmental footprint while prioritizing occupant health.

IEQ also intersects with other LEED categories, such as Energy and Atmosphere and Materials and Resources, highlighting LEED’s integrated approach. For example, efficient ventilation complements energy efficiency by optimizing HVAC systems, and sustainable materials contribute to better air quality by reducing pollutant levels indoors. Together, these interconnected categories create buildings that are environmentally responsible and support a healthy, comfortable, and sustainable indoor experience.

Key Components Of LEED Indoor Environmental Quality

LEED IEQ emphasizes multiple components that address essential aspects of building design and operation. The following are the primary components within the IEQ category, each contributing to a balanced, sustainable environment where occupants can feel comfortable and thrive.

Ventilation And Airflow Management

Proper ventilation helps dilute indoor pollutants and maintain a steady supply of fresh air, which is vital for creating a healthier indoor environment. LEED emphasizes ventilation standards, such as those set by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), which outline optimal airflow rates that balance indoor air quality with energy efficiency.

Effective airflow management involves designing HVAC systems that ensure even distribution and prevent stagnation of air in specific areas. This includes the use of high-efficiency filters, balanced airflow, and strategic placement of vents to maximize air exchange throughout the space. By prioritizing ventilation and airflow management, buildings can reduce pollutants, allergens, and moisture levels, promoting a cleaner, more comfortable environment for occupants.

Low-Emitting Materials

Low-emitting materials are products designed to release minimal volatile organic compounds (VOCs) and other pollutants, reducing indoor air contaminants.

In LEED-certified buildings, low-emitting materials play a crucial role in minimizing exposure to harmful chemicals that can impact occupant health, particularly respiratory health. Using materials that emit fewer pollutants, buildings contribute to better air quality, improving comfort and reducing potential health risks for those indoors. Examples of common low-emitting materials in LEED projects include:

Adhesives and sealants: Low-VOC adhesives and sealants are essential for minimizing off-gassing, which often occurs with conventional products used during construction and renovation.
Paints and coatings: Many LEED-certified buildings use low-VOC or zero-VOC paints and coatings, reducing the release of harmful chemicals that contribute to poor indoor air quality.
Flooring and carpets: Low-emitting flooring materials, including certain carpets and tiles, help maintain healthier indoor air by minimizing chemical emissions.
Furniture and furnishings: Low-emission furniture and furnishings are specifically manufactured to limit the release of formaldehyde and other harmful chemicals often found in synthetic materials and finishes.

Indoor Pollutant Control

Effective pollutant control strategies address both the sources of pollutants and their pathways, reducing the spread of contaminants within indoor spaces. This involves a combination of design practices, filtration systems, and regular maintenance to minimize the presence of allergens, chemicals, and particulates in the air. Key strategies for indoor pollutant control include:

Entryway systems: Installing mats and grates at building entrances helps capture dirt, dust, and other pollutants from shoes, reducing the contaminants brought indoors.
Enhanced filtration: High-efficiency filters in HVAC systems can capture airborne particles and pollutants, improving air quality by removing allergens, dust, and microbial contaminants.
Source control: Choosing building materials, furnishings, and finishes that emit fewer pollutants reduces the initial load of contaminants within the building.
Isolation of high-pollutant areas: Areas prone to higher pollutant levels, such as janitorial closets or printing rooms, are often isolated with separate ventilation systems to prevent pollutants from spreading to common areas.

Daylighting And Views

By bringing more natural light into a building, daylighting reduces the reliance on artificial lighting and creates a pleasant and productive environment for occupants. Exposure to natural light has also been shown to improve mood, support circadian rhythms, and improve overall well-being, making it a valuable element in sustainable building design.

LEED-certified buildings use strategies like large windows, skylights, and strategically placed glazing to optimize daylight penetration throughout interior spaces. These buildings often incorporate open floor plans and low partitions, allowing light to flow more freely within shared areas. To further enhance the indoor experience, LEED promotes providing outdoor views from workstations and other frequently used spaces, giving occupants a visual connection to nature that can reduce stress and improve satisfaction.

How Do These Standards Apply?

LEED standards for indoor environmental quality are crafted to enhance the health and comfort of occupants across various building types, from residential homes to large commercial spaces. Each standard is tailored to address the unique challenges and requirements of different settings. For example, residential buildings often emphasize low-emitting materials and ventilation to ensure a safe living environment. Commercial spaces prioritize efficient air filtration and moisture control to accommodate higher occupancy and activity levels.

By implementing these standards, buildings can create indoor environments that meet rigorous sustainability goals and improve occupant satisfaction and well-being. To ensure a comprehensive approach to indoor environmental quality, LEED standards focus on the following interconnected strategies:

Indoor Air Quality Assessment

LEED’s IAQ Assessment includes two key methods for ensuring air quality: a building flush-out and air testing, each with defined thresholds to confirm indoor air safety.

Building flush-out: This approach involves systematically replacing indoor air with outdoor air to eliminate pollutants introduced during construction. LEED requires a total air volume of 14,000 cubic feet per square foot of floor area to be supplied before occupancy. If the building must be occupied before completing the full flush-out, LEED allows a partial flush-out of 3,500 cubic feet per square foot, followed by continuous ventilation until the total required air volume is met.
Air testing: Alternatively, buildings may conduct air testing to verify that pollutant concentrations are within acceptable LEED-defined thresholds. This testing, conducted post-construction and pre-occupancy, assesses pollutants with specific limits as follows:

Formaldehyde: Must be below 27 parts per billion (ppb)
Particulate matter (PM10): Should not exceed 50 micrograms per cubic meter
Total volatile organic compounds (TVOCs): Should be below 500 micrograms per cubic meter
Carbon monoxide (CO): Must not exceed 9 parts per million (ppm), with no greater than 2 ppm above outdoor levels

For compliance, air testing results must meet these limits to ensure safe, high-quality indoor air. By utilizing these assessment strategies, LEED-certified buildings commit to high indoor air quality standards, enhancing occupant health, comfort, and well-being.

Controlling Indoor Pollutants

LEED emphasizes several effective strategies to control and reduce indoor pollutants, promoting healthier indoor environments. By managing pollutant sources and using non-toxic materials, LEED-certified buildings maintain cleaner air, contributing to overall occupant comfort and well-being. Key strategies include:

Use of low-emitting, non-toxic materials: As mentioned before, LEED encourages the use of materials and finishes with low or zero VOCs, such as low-VOC paints, adhesives, sealants, and flooring. These materials limit the release of harmful chemicals into the indoor environment.
Source control for high-pollutant areas: To prevent contaminants from spreading, areas with high pollutant potential—such as janitorial closets, garages, or print rooms—are often isolated from general areas. These spaces are equipped with separate ventilation systems, keeping pollutants contained and improving air quality in common areas.
Entryway systems: LEED promotes the use of entryway mats or grates to prevent dirt, dust, and other particles from being tracked inside by footwear.
Enhanced filtration systems: High-efficiency filters, such as those with a Minimum Efficiency Reporting Value (MERV) rating of 13 or higher, capture particulates and other airborne contaminants. This is particularly effective in areas with high traffic, or in urban environments with elevated outdoor pollution.
Ventilation management: LEED-certified buildings are designed with ventilation systems that introduce fresh outdoor air while minimizing the recirculation of indoor pollutants. By meeting ASHRAE standards for ventilation rates, LEED helps ensure consistent air exchange, which dilutes indoor pollutants.

By implementing these pollutant control strategies, LEED-certified buildings create safer, cleaner indoor environments that prioritize the health and comfort of occupants, reinforcing the holistic approach to sustainable building design.

Improving Ventilation And Filtration Systems

LEED strongly emphasizes enhanced ventilation and filtration systems to support healthy indoor environments, recognizing that adequate airflow and high-quality filtration are essential for minimizing indoor pollutants and maintaining optimal air quality. Key strategies for improving ventilation and filtration include:

Enhanced ventilation rates: LEED encourages meeting or exceeding ASHRAE 62.1 standards for ventilation, which dictate optimal airflow rates for different building types and occupancy levels. By maintaining these standards, LEED-certified buildings ensure a consistent supply of outdoor air, reducing the buildup of pollutants indoors.
Demand-controlled ventilation (DCV): LEED promotes the use of DCV systems, which adjust ventilation based on real-time occupancy and CO₂ levels. By increasing ventilation in response to higher occupancy, DCV systems help maintain air quality during peak usage while reducing energy consumption when fewer occupants are present.
High-efficiency filtration: LEED recommends high-efficiency particulate air (HEPA) or MERV 13 filters or higher to capture airborne particles, allergens, and pollutants.
Outdoor air intake and exhaust: Properly designed ventilation systems in LEED-certified buildings include adequate outdoor air intake and exhaust systems to maintain airflow balance and ensure pollutants are effectively removed from indoor spaces. This also helps manage moisture levels, reducing conditions that can contribute to mold growth.
Regular maintenance of HVAC Systems: LEED underscores the importance of maintaining HVAC systems to prevent the buildup of dust and contaminants within them. Regular cleaning and timely filter replacement ensure that ventilation and filtration systems operate efficiently over time.

By prioritizing these advanced ventilation and filtration strategies, LEED-certified buildings provide a healthier indoor environment that meets sustainability goals and supports occupant well-being and comfort.

The Intersection Between LEED And EPA Indoor AirPlus Program

The EPA’s Indoor AirPLUS program is designed to ensure healthier indoor environments by reducing exposure to common indoor pollutants, improving ventilation, and addressing moisture control in homes. Created as an add-on to the ENERGY STAR® for Homes certification, Indoor AirPLUS establishes guidelines for home builders to exceed standard indoor air quality practices, providing healthier spaces for occupants.

Indoor AirPLUS complements LEED IEQ by aligning with similar goals to enhance indoor air quality through strategies that minimize contaminants, improve ventilation, and manage moisture. While LEED IEQ focuses broadly on a variety of building types, Indoor AirPLUS is particularly targeted toward residential buildings. This program includes requirements for moisture-resistant materials, radon-resistant construction, and low-emitting materials, all of which align closely with LEED’s pollutant control and ventilation standards.

Together, LEED IEQ and Indoor AirPLUS provide a comprehensive framework for creating healthy, comfortable indoor environments that prioritize occupant well-being and sustainability.

Benefits Of LEED IEQ And EPA Indoor AirPlus Certification

Obtaining certifications like LEED IEQ and EPA Indoor AirPLUS provides significant benefits for building occupants, property owners, and the environment. By meeting rigorous standards for indoor air quality, ventilation, and pollutant control, these certifications ensure a healthier indoor environment, enhanced air quality, and a reduced ecological footprint. These advantages make certified buildings more appealing to both occupants and investors, aligning with modern expectations for sustainable and health-conscious spaces.

Health Benefits For Occupants

Arguably the primary benefit of LEED IEQ and EPA Indoor AirPLUS certification is the direct impact on occupant health. Certified buildings maintain strict standards for air quality, reducing the presence of pollutants like VOCs, formaldehyde, and particulate matter. Health benefits include:

Reduced respiratory irritation: Certified buildings help lower exposure to irritants by using low-emitting materials and enhanced ventilation systems, reducing respiratory issues and allergic reactions.
Improved cognitive function: Proper ventilation and CO₂ control have been shown to improve cognitive performance and alertness, which can be especially beneficial in work and learning environments.
Minimized risk of illness: Effective pollutant control and humidity management help reduce the presence of mold, allergens, and other contaminants that can contribute to chronic respiratory conditions or immune system stress.

Environmental And Energy Efficiency Gains

LEED IEQ and Indoor AirPLUS certifications also deliver environmental and energy efficiency benefits that contribute to a building’s overall sustainability. Key advantages include:

Reduced environmental impact: These certifications help lower a building’s environmental footprint by encouraging the use of sustainable, non-toxic materials and efficient ventilation systems. They also reduce the release of pollutants and VOCs.
Optimized energy use: Both certifications prioritize energy-efficient ventilation systems, such as demand-controlled ventilation (DCV) and high-efficiency filters, which maintain air quality without excessive energy consumption.
Enhanced market value and sustainability profile: Properties with LEED IEQ and Indoor AirPLUS certifications often experience higher market value and a reputation for sustainability, appealing to eco-conscious investors and occupants.

By prioritizing health, sustainability, and energy efficiency, LEED IEQ and EPA Indoor AirPLUS certifications create spaces that support both environmental responsibility and occupant well-being, providing long-term value and adaptability in an increasingly eco-focused market.

How redT Homes Support LEED Indoor Environmental Quality Standards

At redT Homes, we are dedicated to integrating LEED IEQ standards across all facets of our services, ensuring that each project meets or exceeds LEED Gold certification. Our comprehensive approach spans design, architecture, and construction, all aimed at creating healthier, more sustainable living environments.

Our in-house architecture team meticulously designs homes with a focus on sustainability and occupant well-being. We reduce indoor pollutants by selecting low-emitting materials and incorporating enhanced ventilation systems, aligning with LEED IEQ criteria. Additionally, our designs maximize natural light and outdoor views, promoting a strong connection to nature and enhancing indoor environmental quality.

During construction, we implement rigorous quality control measures to maintain high indoor air quality. This includes protecting ventilation systems from contamination and conducting thorough air quality assessments before occupancy. Our commitment to sustainable building practices ensures that each home not only meets LEED standards but also provides a healthy living space for our clients.

By seamlessly integrating LEED IEQ standards into every stage of our projects, redT Homes delivers residences that are both environmentally responsible and supportive of occupant health and comfort.

Implement LEED IEQ In Your Building Projects For Sustainability

Incorporating LEED IEQ standards into building projects is essential for fostering healthier, more sustainable indoor environments. Practical steps to achieve LEED IEQ certification include focusing on enhanced ventilation, using low-emitting and non-toxic materials, controlling indoor pollutants, and maximizing natural light.

The benefits of implementing LEED IEQ standards extend beyond health. These practices support sustainability by reducing a building’s environmental footprint and enhancing energy efficiency through strategies like demand-controlled ventilation and high-efficiency filters. Over time, the commitment to LEED IEQ leads to long-term cost savings, as improved air quality and efficient systems reduce the need for repairs and health-related expenses.

By following LEED IEQ guidelines, you can create spaces that prioritize occupant well-being, contribute to environmental goals, and offer valuable financial benefits through sustainable, resilient design.

Learn how redT Homes can help you implement LEED IEQ standards and build healthier, sustainable homes.