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Rethinking HVAC: Decarbonization, Energy Efficiency, and Indoor Air Quality

Decarbonizing HVAC systems cuts emissions and boosts efficiency. Explore how sustainable HVAC tech is transforming indoor air quality.

Ava Montini

Nov 14, 2024

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In an era where climate change, energy consumption, and public health intersect, the way we design, operate, and innovate within our buildings has never been more critical. At the heart of this transformation lies the HVAC (Heating, Ventilation, and Air Conditioning) system.


Although typically hidden from sight, HVAC infrastructure plays a crucial role in energy use, indoor air quality (IAQ), and carbon emissions. A closer look reveals that HVAC systems profoundly impact a building’s functionality, environmental footprint, public health outcomes, and operational efficiency.

The Energy-Intensive Reality of HVAC Systems

HVAC systems are among the largest energy consumers in residential and commercial buildings, often responsible for a significant portion of a building’s operating costs and environmental footprint. In the United States alone, HVAC accounts for approximately 35% of a building's energy consumption, a figure that can be even higher in colder and warmer climates due to increased heating and cooling demands. According to the 2021 Global Status Report for Buildings and Construction by the GlobalABC, the buildings sector accounted for 36% of global final energy consumption and 37% of energy-related CO₂ emissions in 2020.


Historically, HVAC systems have been energy-intensive by nature, using vast amounts of power to regulate temperature and maintain air quality within a building. This often places HVAC at the center of energy-saving and decarbonization initiatives. However, balancing energy efficiency with effective indoor air quality control has proven challenging.


Ventilation, which is essential for good IAQ, typically requires large volumes of air to be exchanged, a process that consumes significant energy and raises costs. This trade-off between energy savings and IAQ improvement has long hindered the HVAC industry’s transition to sustainable practices.


The Cost of Compromised Indoor Air Quality

Indoor air quality plays a vital role in health, well-being, and productivity. Poor IAQ has been linked to respiratory diseases, allergies, and even mental fatigue, while the economic cost of inadequate IAQ often goes unmeasured. The World Health Organization estimates that air pollution contributes to more than 4 million premature deaths each year, with indoor air pollution being a significant factor. Studies indicate that improved IAQ can reduce health risks and enhance cognitive function, particularly in office and educational settings where individuals spend extended hours indoors.


A study by the Harvard T.H. Chan School of Public Health found that participants in green office environments experienced a 61% improvement in cognitive scores, while those in green+ environments with enhanced ventilation saw scores double compared to conventional settings, underscoring the link between IAQ and productivity. Improved indoor air quality also reduces absenteeism, as shown by a U.S. Environmental Protection Agency (EPA) study reporting a 10% decrease in student absences with better IAQ, and additional research indicating that increased office ventilation can reduce short-term employee absences by 35%. These findings emphasize the importance of maintaining optimal IAQ in both educational and professional settings for health and productivity.


Comparing Outdoor vs. Indoor Air Quality

While outdoor air pollution often captures public attention, indoor air pollution can pose even greater health risks, largely because people spend nearly 90% of their time indoors. Without proper ventilation and filtration, indoor spaces can accumulate pollutants over time, creating high-risk environments even in areas where outdoor air is relatively clean. Indoor pollutants, such as volatile organic compounds (VOCs) from cleaning products, chemicals from building materials, and particulate matter from HVAC systems, often reach levels that are two to five times higher than outdoor levels. Compounding this, outdoor pollution or environmental factors, like wildfire smoke or high pollen counts, can seep indoors, adding to the burden on indoor air quality if not properly managed.


Bridging the Gap Between IAQ and Energy Efficiency

The perception that energy savings and optimal IAQ are mutually exclusive has evolved with advances in HVAC technology. New systems now offer solutions that provide fresh, filtered air without excessive energy consumption. Energy-efficient HVAC systems are equipped with features like variable-speed compressors, heat exchangers, and intelligent sensors that adjust airflow based on occupancy and usage patterns, more effectively balancing IAQ and energy use.


Key Technologies Redefining IAQ and Energy Efficiency in HVAC:

  1. Variable Refrigerant Flow (VRF) Systems: These systems allow precise control over the cooling and heating of each zone within a building, reducing energy consumption by eliminating the need to heat or cool unused areas.


  2. Heat Recovery Ventilation (HRV) Systems: HRVs reclaim heat from outgoing air and transfer it to incoming air, reducing the energy required to maintain indoor temperatures.


  3. Demand-Controlled Ventilation (DCV): DCV uses sensors to monitor CO2 levels and occupancy within a space, adjusting ventilation rates dynamically. This reduces unnecessary energy use and enhances air quality by providing fresh air only when needed.


  4. Low-Pressure Advanced Filtration: Low-pressure polarized filters efficiently capture pollutants like VOCs and fine particles with minimal airflow resistance, supporting energy and operational efficiency.


  5. Smart Thermostats and Building Automation: These systems enable HVAC units to operate at optimal efficiency by learning usage patterns, predicting occupancy, and adjusting temperature and ventilation levels based on real-time data.


The Role of HVAC in Building Decarbonization

With buildings accounting for nearly 40% of global energy consumption, they play a significant role in carbon emissions. Decarbonizing HVAC systems involves reducing direct emissions from fossil-fuel systems and minimizing indirect emissions through energy efficiency improvements. Efforts to decarbonize increasingly focus on electrifying heating, integrating renewable energy, and adopting advanced technologies that can greatly lower a building’s carbon footprint.


Pathways to Decarbonize HVAC Systems:


  1. Electrification of HVAC: Transitioning from gas boilers and furnaces to electric heat pumps can significantly cut direct emissions from fossil fuels. Paired with renewable energy sources, electric heat pumps further reduce both emissions and operating costs.


  2. Use of Renewable Energy: Integrating renewable sources like solar panels and wind power with HVAC systems reduces reliance on grid electricity. When HVAC systems are powered by renewable energy, buildings can move closer to achieving net-zero emissions.


  3. District Heating and Cooling Systems: Serving multiple buildings from a centralized plant, district heating and cooling systems dramatically reduce energy consumption and emissions. These systems are highly effective in urban areas and industrial complexes, where centralized efficiency can impact entire communities.


  4. Energy Storage and Peak Shaving: Battery storage systems allow buildings to store off-peak energy for later use, lowering demand on the grid and reducing costs. This approach also decreases the carbon footprint by reducing peak-time energy consumption.


  5. Low-Pressure, High Dust Loading Filtration: Low-pressure, high dust-loading filtration technology enables HVAC systems to maintain excellent indoor air quality without increasing energy consumption. By reducing strain on HVAC systems, these filters help optimize energy usage, creating a balanced, low-energy approach to superior indoor air quality. In high-traffic and sensitive environments, this filtration technology promotes sustainability and health but also contributes to lower peak energy demand and overall kWh usage.


Smart HVAC through Real-Time Data and Technology

Smart HVAC systems leverage IoT sensors, AI, and machine learning to enhance building management by providing real-time insights into temperature, occupancy, and indoor air quality (IAQ). IoT sensors enable systems to adjust settings based on occupancy and external conditions, optimizing comfort and reducing energy use. For example, unoccupied zones can automatically receive less heating or cooling, saving energy without sacrificing comfort.


Predictive maintenance is another key feature. It uses data to anticipate and address minor issues before they escalate, reducing repair costs and extending system lifespan. Machine learning further enhances efficiency by learning from usage patterns to optimize settings dynamically, reducing overall energy consumption. IAQ sensors adjust ventilation in response to pollutants, ensuring healthy indoor air, especially in high-occupancy environments like schools and hospitals.


This adaptive functionality not only lowers operational costs and peak energy demand but also supports sustainability goals by reducing carbon footprints. Smart HVAC systems offer continuous optimization, making buildings more resilient, efficient, and environmentally responsible.


Economic Incentives for Sustainable HVAC Systems

The economic benefits of sustainable HVAC upgrades are extensive. Although energy-efficient technology often requires an initial investment, the long-term savings in reduced energy bills can be substantial. Additionally, building owners may qualify for government incentives, grants, and rebates aimed at supporting energy-efficient retrofits. These financial incentives help offset initial costs, making sustainable HVAC upgrades more financially accessible.


Examples of Government Incentives

These incentives make sustainable HVAC systems more affordable and accessible, encouraging widespread adoption and supporting overall energy efficiency and decarbonization efforts.


Future-Proofing Buildings with Sustainable HVAC Solutions

The global transition to net-zero emissions by 2050 hinges on making our built environments sustainable and resilient. HVAC systems, with their substantial energy demands and carbon impact, are essential to this transformation. By embracing energy-efficient and decarbonized HVAC technologies, we can future-proof buildings against rising energy costs, regulatory changes, and environmental pressures.


This shift goes beyond simply improving IAQ or reducing energy bills; it’s about creating spaces where sustainability, health, and operational efficiency coexist. Clean, breathable air is not just a perk—it’s a necessity for well-being and productivity. Likewise, efficient, low-emission buildings are essential for a low-carbon economy.



The future of HVAC is evolving in a way that aligns energy efficiency, decarbonization, and indoor air quality as complementary goals. This shift challenges the traditional trade-offs between these objectives, proving that clean air and efficient energy use can coexist without compromise. HVAC systems of the future will be integrated, smart, and sustainable, paving the way for buildings that are not only more environmentally responsible but also healthier and more enjoyable to inhabit.


With ongoing innovations in HVAC technology, we are reaching a point where buildings can actively contribute to sustainability and public health, setting a new standard for what it means to operate a truly green building. By adopting these advanced systems, we are moving toward a reality where indoor spaces can maintain optimal air quality, reduce energy waste, and significantly cut emissions, creating a cleaner, more sustainable world.

Writer's pictureJennifer Crowley

The Importance of Indoor Air Quality in Older Buildings

Older building rooftop ventilation
Older buildings often face several air quality challenges due to years of accumulated wear and tear and outdated construction practices.

Indoor air quality (IAQ) is a critical aspect of building management that directly affects the health and well-being of occupants. This importance is magnified in older buildings, where outdated infrastructure, prolonged wear and tear, and the presence of potentially hazardous materials can significantly compromise air quality.


For building owners and facility managers, ensuring good air quality in older buildings is not just a matter of comfort; it is essential for maintaining the health and safety of those who live and work in these environments. Poor IAQ in such buildings can lead to various health issues, decreased productivity, and non-compliance with modern regulatory standards, making it a fundamental concern that demands urgent action.


Common Air Quality Issues in Older Buildings

Older buildings often face several air quality challenges due to years of accumulated wear and tear and outdated construction practices. These issues can severely impact IAQ, making it crucial to identify and address them to ensure a healthy living and working environment. Common air quality problems in older buildings include:


  • Mold and Mildew: Due to water damage or high humidity, mold and mildew can thrive in older buildings, releasing spores into the air.

  • Dust and Allergens: Accumulated dust and debris in older buildings can harbor allergens, worsening respiratory conditions.

  • Outdated HVAC Systems: Inefficient and outdated HVAC systems may not adequately filter air, leading to the circulation of pollutants.

  • Asbestos and Lead: Many older buildings still contain asbestos and lead-based materials, which can pose serious health risks if disturbed.

  • Chemical Pollutants: Use of old construction materials and maintenance products can introduce volatile organic compounds (VOCs) into the indoor environment.


Health Impacts

Young multi-racial woman clutching her chest and coughing while attempting to use a rescue inhaler
Exposure to contaminants seen in older buildings can result in many adverse health effects.

The poor indoor air quality in older buildings can lead to numerous health problems for occupants, emphasizing the need for immediate attention. Exposure to contaminants commonly found in older buildings can result in a range of adverse health effects, including:


  • Respiratory Issues: Exposure to mold spores, dust, and other airborne pollutants can exacerbate asthma, bronchitis, and other respiratory conditions.

  • Allergies: Increased levels of allergens such as dust mites and pollen can trigger allergic reactions, leading to discomfort and reduced quality of life.

  • Productivity Loss: Poor air quality can cause headaches, fatigue, and difficulty concentrating, reducing productivity and overall well-being.

  • Long-Term Health Risks: Chronic exposure to pollutants like asbestos and lead can lead to severe health conditions, including cancer and neurological disorders.


Regulatory Concerns in Older Buildings

Ensuring compliance with air quality standards and regulations is critical for older buildings, as failing to meet these requirements can lead to significant health risks and legal issues. Both Canada and the US have established stringent guidelines to protect indoor air quality, but older buildings often struggle to meet these standards due to several factors:


Canadian Regulations:

  • Health Canada: Sets IAQ guidelines that include maximum acceptable concentrations for common indoor pollutants such as carbon monoxide, formaldehyde, and mold spores. Older buildings might not have adequate ventilation systems to meet these guidelines.

  • National Building Code of Canada: Requires proper ventilation and air filtration systems to maintain acceptable IAQ. Many older buildings were constructed before these codes were established, leading to inadequate ventilation and outdated HVAC systems.

  • Provincial Regulations: Provinces like Ontario have specific requirements under the Ontario Building Code, focusing on ventilation and mold prevention. Older buildings often lack the modern infrastructure necessary to comply with these regulations. The Canadian Centre for Occupation Health and Safety provides a great resource to link to provincial guidance.

  • See also ASHRAE Standards below


United States Regulations:

  • Environmental Protection Agency (EPA): Establishes IAQ guidelines and provides resources for maintaining healthy air in buildings. The EPA’s standards include acceptable levels for various indoor pollutants. Older buildings often have outdated or poorly maintained HVAC systems that fail to filter out pollutants effectively.

  • Occupational Safety and Health Administration (OSHA): Mandates safe working conditions, including standards for indoor air quality in workplaces. Older buildings may not meet these standards due to deteriorating infrastructure and lack of modern air purification systems.

  • ASHRAE Standards: The American Society of Heating, Refrigerating, and Air-Conditioning Engineers sets voluntary IAQ standards that are widely adopted, covering ventilation rates and air filtration. Older buildings may not have been designed to meet these standards, resulting in subpar IAQ.


Older buildings often fail to meet these standards due to outdated infrastructure and lack of modern air filtration systems, which can result in regulatory fines and increased health risks for occupants. Additionally, many of these buildings were constructed before current IAQ standards were established, making retrofitting necessary but often challenging and costly.


Indoor Air Quality in Older Buildings Case Study

Toronto Distillery District Energy Efficiency & IAQ Project

The Historic Gooderham & Worts Distillery District, opened in 2003, is widely regarded as Ontario's premier arts, culture, and entertainment destination, and one of its hottest tourist attractions. This internationally acclaimed village features brick-lined streets and 47 vibrantly restored 19th-century Victorian industrial buildings. As a major dining, shopping, and cultural hub in Toronto, Canada, the importance of maintaining and upgrading these historic buildings to achieve better indoor air quality (IAQ) is paramount.

Blade Air Electromagnetic Pro Filter
Blade Air Pro Filters capture particles 40 times smaller than traditional filters.

In December 2021, the Distillery District management team sought Blade Air's help to improve IAQ without the high costs and energy demands of HEPA or UV solutions. They needed an efficient, cost-effective solution to enhance air quality while reducing their carbon footprint.


Blade Air recommended their Pro Filter electromagnetic filters, which outperform HEPA filters in capturing particulate matter and inactivating viruses, with significantly lower energy requirements. The Distillery District conducted trials in two buildings, resulting in impressive outcomes:


  • Energy Savings: Up to 75% reduction in fan motor consumption.

  • Improved Filtration: 2.25 times better performance in capturing and removing bacteria from the airstream compared to MERV-13 filters.

  • Enhanced Air Quality: Significant improvement in indoor air quality, creating a healthier environment for occupants.

  • Cost-Effective Solution: Achieved high efficiency and superior air quality without the prohibitive costs of HEPA or UV solutions.


Upgrading these historic buildings with modern air quality solutions ensures they continue to be a safe, healthy, and attractive destination for visitors and tenants alike. Click here to read the full Case Study.


Blade Air IAQ Solutions

For building owners and facility managers, addressing IAQ is not just a regulatory requirement but a fundamental concern that directly impacts the health and satisfaction of occupants. The adverse effects of poor air quality, from respiratory issues to productivity loss, highlight the need for immediate action.


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Blade Air is Your Trusted Partner in IAQ for Older Buildings.

By implementing Blade Air’s solutions, you can ensure your building meets and exceeds current air quality standards, safeguarding health, avoiding potential legal and financial repercussions, and creating safer, healthier environments for everyone.


Blade Air is dedicated to providing expert guidance and retrofitting services to help you achieve these goals. Contact Blade Air today to learn how we can help transform the air quality in your building, ensuring a healthier and more comfortable environment for all occupants.

Explore expert insights, stay up to date with industry events, and gain a deeper understanding of the cutting-edge developments that are revolutionizing the indoor air quality landscape within Blade Air's comprehensive Insights Hub.

You can also subscribe to our monthly newsletter below for exclusive early access to Blade's Insights content, uncovering tomorrow's air quality advancements before they hit our Hub.

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