The air inside a building affects health, comfort, and productivity every single day \u2014 often more than people realize. While outdoor air quality gets most of the public attention, indoor air is typically two to five times more polluted, and people spend roughly 90 percent of their time indoors. For building owners and facility managers, understanding and actively managing indoor air quality has become essential rather than optional. This guide covers three connected services that form the foundation of a modern indoor air quality strategy: indoor air quality testing, demand controlled ventilation, and IAQ monitoring systems.<\/p>\n\n\n\n
Indoor air quality (IAQ)<\/a> has moved from a niche facilities concern to a central factor in occupant health, regulatory compliance, and building value. Poor IAQ has been linked to headaches, fatigue, respiratory irritation, and reduced cognitive performance, while research has connected better ventilation to measurable improvements in decision-making speed and accuracy. At the same time, a growing number of jurisdictions and industry standards now require documented ventilation performance, pushing IAQ from a “nice to have” into a compliance requirement for many building types, including schools, healthcare facilities, and commercial offices.<\/p>\n\n\n\n The three services covered here work together as a complete cycle: testing identifies the problem, demand controlled ventilation solves part of it efficiently, and monitoring keeps it solved over time.<\/p>\n\n\n\n Indoor air quality testing is the diagnostic starting point for any IAQ initiative. It involves measuring specific pollutants and environmental conditions inside a building to establish a baseline, identify problem areas, and guide corrective action. Without testing, facility teams are essentially guessing at what’s actually in the air occupants breathe.<\/p>\n\n\n\n What gets tested.<\/strong> A thorough IAQ assessment typically measures carbon dioxide (CO2) as a proxy for ventilation adequacy, particulate matter (PM2.5 and PM10), volatile organic compounds (VOCs) from furniture, cleaning products, and finishes, carbon monoxide, relative humidity and temperature, and in some cases mold spores, radon, or formaldehyde depending on building type and occupant concerns. Airflow and ventilation rates are also measured directly at diffusers and air handling units to confirm the system is actually delivering the outdoor air it was designed to provide.<\/p>\n\n\n\n How testing is performed.<\/strong> Testing generally combines short-term spot measurements using calibrated handheld instruments with longer-duration monitoring, sometimes spanning several days or weeks, to capture how conditions change with occupancy, weather, and HVAC operating cycles. A single point-in-time reading can miss problems that only appear during peak occupancy or specific seasons, so a combination of approaches gives a more complete and reliable picture.<\/p>\n\n\n\n When testing is needed.<\/strong> Common triggers include occupant complaints about stuffiness, odors, or health symptoms; a building renovation or change in space use; preparation for LEED or WELL certification; post-construction verification; or as part of a routine preventive maintenance program. Many organizations now schedule testing annually or seasonally rather than waiting for complaints, since problems caught early are almost always less expensive to fix.<\/p>\n\n\n\n What happens after testing.<\/strong> Results are compared against recognized benchmarks such as ASHRAE Standard 62.1 for ventilation and EPA or WELL Building Standard guidelines for pollutant concentrations. A written report typically identifies which areas or systems are underperforming and recommends specific corrective actions, which often include the two solutions covered next: demand controlled ventilation and ongoing monitoring.<\/p>\n\n\n\n Traditional HVAC systems often ventilate spaces on a fixed schedule, delivering the same amount of outdoor air whether a conference room is empty or packed. Demand controlled ventilation solves this mismatch by adjusting the rate of outdoor air brought into a space based on real-time occupancy, most commonly measured through CO2 sensors.<\/p>\n\n\n\n How it works.<\/strong> As people occupy a space, they exhale CO2, and concentrations rise. A DCV system continuously monitors CO2 levels in occupied zones and signals the building automation system to increase outdoor air ventilation when levels climb and reduce it when the space is lightly occupied or empty. This keeps ventilation matched to actual need rather than a worst-case fixed assumption.<\/p>\n\n\n\n Where it delivers the most value.<\/strong> DCV is particularly effective in spaces with highly variable occupancy, such as conference rooms, auditoriums, classrooms, gyms, and open-plan offices with flexible schedules. In these spaces, fixed ventilation rates sized for maximum occupancy waste enormous amounts of conditioned outdoor air during the many hours the space is partially used or empty.<\/p>\n\n\n\n The energy and comfort case.<\/strong> Conditioning outdoor air<\/a> \u2014 heating or cooling it to match indoor setpoints \u2014 is one of the more energy-intensive tasks an HVAC system performs. By reducing unnecessary ventilation during low-occupancy periods, DCV can meaningfully cut heating and cooling energy use while maintaining or even improving comfort, since ventilation increases automatically when it’s actually needed rather than lagging behind a fixed schedule. Many organizations see DCV pay for itself through energy savings within a few years, particularly in climates with significant heating or cooling loads.<\/p>\n\n\n\n Implementation considerations.<\/strong> Successful DCV requires properly located and calibrated CO2 sensors, a building automation system capable of modulating outdoor air dampers or variable air volume boxes, and sequences of operation that are commissioned and verified rather than simply installed and left alone. Retrofitting DCV into an existing building is often more cost-effective than many owners expect, especially when combined with a broader controls upgrade or retro-commissioning project.<\/p>\n\n\n\n While testing provides a snapshot and DCV actively manages ventilation, an IAQ monitoring system provides continuous, ongoing visibility into indoor air conditions across a facility. Rather than waiting for the next scheduled test or an occupant complaint, monitoring systems track air quality around the clock and alert facility teams the moment conditions drift outside acceptable ranges.<\/p>\n\n\n\nIndoor Air Quality Testing<\/h2>\n\n\n\n
Demand Controlled Ventilation (DCV)<\/h2>\n\n\n\n
IAQ Monitoring Systems<\/h2>\n\n\n\n