Why Measure CO2 For IAQ And HVAC?

Scientific studies have demonstrated that monitoring CO2 for HVAC, rather than just for temperature or humidity, can significantly increase energy efficiency and save costs. Not only that, controlling CO2 emissions can enhance workplace productivity.

Improving Workplace Alertness &  Productivity

Researchers have shown that CO2 levels above 1000ppm can negatively impact on concentration and increases lethargy in the workplace.

The graph below shows how indoor CO2 levels can increase to 1000ppm in 50 minutes, demonstrating the need for adequate ventilation.

Image source: Edaphic Scientific

7 reasons for measuring CO2 inside buildings

  • CO2 can kill – TheCanadian Centre for Occupational Health and Safety has provided detailed information on how CO2 can be a hazardous gas under many circumstances.
  • Productivity decreases with increasing CO2 – Generally, CO2 concentrations at 1,000ppm can lead to a statistically significant decrement in decision making performance
  • This gas can rapidly increase in poorly ventilated rooms – Generally, where large numbers of people gather then CO2 will increase rapidly and lead to poor indoor air quality and pollution.
  • Some locations have naturally high levels of CO2, requiring monitoring – There are certain locations where indoor CO2 in an enclosed room or area can potentially reach extreme and life threatening levels.
  • Increases energy efficiency have been shown – One study found that monitoring CO2 for DVC saved between 5 and 80% on energy costs compared with a fixed ventilation strategy.
  • Improvements in Green Building scores can be expected The Green Building Council of Australia scores 1 to 2 points if CO2 levels are maintained below 800ppm or 700ppm respectively.
  • Measuring and managing indoor air quality demonstrates leadership – Measuring indoor levels of CO2 is new to most people and generates interest.

Measuring Indoor Air Quality (IAQ)

IAQ measurements are designed to characterize the amount of outdoor air that is delivered to occupants, comfort indicators, the performance of the HVAC system, pressure relationships, and air flow patterns that could transport contaminants from potential sources to the occupied areas of the building.

Indoor Air Quality (IAQ) refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants. Understanding and controlling common pollutants indoors can help reduce your risk of indoor health concerns.

Health effects from indoor air pollutants may be experienced soon after exposure or, possibly, years later.

The US Environmental Protection Agency (EPA) considers an IAQ investigation to be like detective work – defining the problem, looking for clues, and finding a solution through an iterative process of narrowing the possible causes, and developing and testing hypotheses.

Tools to measure CO2


CO2 detectors provide a dependable and low-cost solution for demand controlled ventilation (DVC). CO2 detectors are ideal where room occupancy is intermittent or variable from original design conditions.

Building performance rating tools, such as Green Star and NABERS, specifically require monitoring of CO2 levels to score points. As an example from the list above, the Green Building Council of Australia scores 1 to 2 points if CO2 levels are maintained below 800ppm or 700ppm respectively.

CO2 detectors can pay for themselves over several months (depending on size and type of installation).

Ultimately, the end result of deploying such tools will provide a safer and more productive IAQ setting


This article has been sponsored by Edaphic Scientific

Images via Shutterstock & Edaphic Scientific


Leave a Reply