Facility Changes That Drive 80% of Emissions Savings

The overlooked 20% of building strategies can deliver 80% of emissions savings. Here’s how to reset your 2026 baseline.

Ava Montini

Jan 6, 2026

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The 80/20 Pattern in Building Decarbonization

In business, the Pareto principle (the idea that 20% of actions create 80% of results) shows up everywhere. It also applies to the way buildings decarbonize.

Most portfolios still treat carbon reduction as a capital-projects problem: new chillers, new boilers, new equipment. These projects are visible, expensive, and easy to headline in ESG reports. But in practice, the biggest near-term gains lie in the systems that are already running every hour of every day.

According to the U.S. Energy Information Administration, space heating, cooling, and ventilation are among the top energy end-uses in commercial buildings, with ventilation alone consuming nearly 10% of the total building energy. Factor in heating and cooling, and the air systems you already own set the floor for your emissions profile. Industry surveys and guidance reinforce this point: HVAC systems consistently account for approximately 40% of energy use in commercial facilities. A share that shifts by climate zone but remains dominant across the board.

Before you buy new megawatts, make the watts you already use travel a shorter, smarter, more efficient path.

Filtration as a carbon multiplier (not a consumable line item)

Why filtration matters for energy (and CO₂e)

Filters impose a pressure drop; fans work against that resistance. Basic fan/affinity laws tell us that pressure rises with the square of fan speed, and fan power typically scales with pressure/flow requirements. Therefore, adding resistance increases fan energy unless the system compensates by reducing the flow.

On variable-speed systems that maintain flow, peer-reviewed work shows roughly linear fan-power response to added system pressure: a 10% rise in total pressure drop ≈ 10% rise in fan electric power (assumes fan and motor efficiencies roughly constant at operating point). CaEE

Field and lab studies show that higher filter resistance reduces supply airflow and can increase total power (especially as filters load), degrading cooling capacity and forcing longer runtimes. Newer research also documents the compounding effects of filter loading, with heavy clogging cutting net supply airflow by >30%, a textbook example of invisible energy waste. ScienceDirect

Moving up in MERV doesn’t automatically mean higher energy costs. Well-designed filters use optimized media and geometry (like deeper pleats or more surface area) to keep airflow resistance low. Studies have shown that these higher-efficiency filters can have a lower pressure drop than inexpensive MERV 8 pleated filters, especially when systems are properly balanced. In other words, it’s the filter’s pressure profile that matters, not just the MERV number. ScienceDirect

If you can lower your filter pressure drop while maintaining or improving capture, you directly reduce continuous fan energy. One of the few all-hours loads in many facilities. Because fans run whenever you condition or ventilate space, these savings translate cleanly into CO₂e reductions (see Section 5 for the math).

Demand-Controlled Ventilation (DCV)

What DCV does

It modulates outside-air intake based on occupancy (CO₂, people-count, scheduling) to avoid conditioning empty spaces. Codes and standards increasingly require or encourage DCV in high-occupancy areas, with ASHRAE 62.1 updates clarifying when and how ventilation turndown is permitted (including addenda that allow reduction to zero OA during verified unoccupied periods in certain space types). ASHRAE

Across building types and climates, published work shows that DCV control logic achieves ~9–33% HVAC energy savings. Advanced rooftop-unit control packages, which incorporate multi-speed/variable fans, DCV, and smarter economizer control, have delivered double-digit fan and cooling savings, sometimes exceeding 20%. Taylor & Francis Online

Lawrence Berkeley National Laboratory (LBNL) analyses flag that cost-effectiveness depends on the baseline over-ventilation and occupancy patterns; if your current minimums are already close to code, savings shrink. That’s a guidance feature, not a flaw—the point is to measure your baseline VRs before projecting benefits. Energy Technologies Area

DCV is a surgical lever: attack over-ventilation where it exists, prove reductions with trend data, and lock in permanent load reductions; especially valuable in heating-dominated regions where conditioning outside air is expensive in both energy and CO₂e. Energy Codes Guide

Preventative Maintenance

Controls drift, coils foul, dampers stick, sensors mis-calibrate—quietly taxing 5–15% of portfolio energy in many studies. Modern fault detection & diagnostics (FDD) tools and structured maintenance programs quickly recapture that waste. NREL Docs

Coil fouling: Government and academic sources document material energy penalties from dirty coils; some guidance cites compressor energy up to ~30% higher with fouled condensers (case and climate dependent). Even conservative findings confirm meaningful efficiency and capacity degradation. Avoidable with routine cleaning. Energy.gov.au
Economizers & OA paths: Mis-tuned economizers are common and costly; retuning and sensor QA via FDD is repeatedly highlighted in DOE/NREL/PNNL guidance as a top-tier low-cost fix. PNNL
RTU controls refresh: Campaign results and tech briefs demonstrate that advanced RTU control (variable fan, DCV, and economizer optimization) consistently yields energy reductions of more than 20%, with 25–50% reductions cited in certain deployments compared to legacy constant-speed, always-open baselines. Better Buildings Solution Center

Maintenance is mitigation. It’s also Scope 3-friendly: operating equipment at design efficiency extends service life and defers replacements, reducing embodied carbon churn in your capital plan. (See the measurement plan below to make these savings auditable.)

Turning kWh into CO₂e: a quick, defensible method

Your sustainability stakeholders care about tons, not watts. To translate HVAC savings into CO₂e:

Quantify energy from the measure (e.g., fan kWh drop from low-pressure filters; heating/cooling kWh or therms saved from DCV; kWh saved from FDD fixes).
Apply grid or fuel emission factors appropriate to the site(s) and year.
- U.S. electricity (2022 eGRID avg): ≈ 0.393 kg CO₂/kWh (867.5 lb/MWh delivered). US EPA+1
- Canada electricity (2025 factors) vary widely by province—e.g., Ontario: 38 g CO₂e/kWh; Alberta: 490 g CO₂e/kWh. Selecting the right regional factor matters. Canada.ca

If a low-pressure filter reduces fan energy by ~300 kWh/year per unit (magnitude depends on hours, fan size, and baseline pressure):

U.S. eGRID avg: 300 kWh × 0.393 kg/kWh ≈ 118 kg CO₂e/year per filter.
Ontario: 300 kWh × 0.038 kg/kWh ≈ 11 kg CO₂e/year per filter.

This is why portfolios across different grids see very different CO₂e per kWh outcomes. Even when the kWh savings are identical. US EPA

For transparency in ESG filings, reference the EPA eGRID subregion or the Government of Canada tables (or your utility-specific factors) and archive the PDFs used for each reporting year. US EPA

Risk management & IAQ alignment

Stay within ASHRAE 62.1 minimums at all times when spaces are occupied. DCV is about right-sizing, not starving air. Updated addenda clarify occupancy-based turndown rules—use them. ASHRAE
Filter choices: Seek equal or higher capture with lower ΔP; measure clean and loaded ΔP at your own face velocities. Research shows energy impact depends on filter design and system configuration, not only MERV. ScienceDirect
Measurement culture: Treat IAQ and energy as co-optimized objectives by trending PM, CO₂, temperature, and fan power together, so nobody is flying blind.

What this unlocks for 2026 capex

Once you bank the operational tons above, the economics of electrification, heat recovery, and heat pumps improve because you’re sizing for reduced loads. DOE/NREL work on advanced RTU control consistently shows meaningful kWh reductions when variable fans and DCV are layered in—think of these as pre-project multipliers that de-risk later capex. NREL Docs

The Power of the Overlooked 20%

In the rush to decarbonize, it’s tempting to chase the biggest, newest technologies. But the truth is that many of the most reliable carbon savings are already within reach. Hidden in fans, filters, ventilation rates, and maintenance routines.

Filtration, demand-controlled ventilation, and preventative maintenance may not make the headlines, but together they represent the overlooked 20% of actions that can deliver 80% of your emissions savings. They are measurable, repeatable, and scalable across portfolios, exactly the kind of solutions facility leaders need as they enter a new year of climate commitments.

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

Ava Montini
Nov 14, 2024
7 min read

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:

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.
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.
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.
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.
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:

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.
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.
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.
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.
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

U.S. Environmental Protection Agency’s (EPA) ENERGY STAR Program provides incentives for buildings that meet energy efficiency standards, encouraging the adoption of sustainable practices.
Canada’s Greener Homes Grant offers up to $5,000 in rebates for energy-efficient upgrades, including HVAC systems, to promote sustainability in residential buildings.
Ontario’s Save on Energy Program provides financial incentives for energy-efficient upgrades in both residential and commercial buildings. This includes rebates for HVAC upgrades that lower energy consumption and improve efficiency.
California’s Self-Generation Incentive Program (SGIP) provides rebates or tax credits for energy-efficient HVAC installations, covering technologies like battery storage that further reduce energy demand on the grid.

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.