June 10, 2025

Improving Indoor Air Quality with CO₂ Monitoring in HVAC Systems

Indoor air quality is vital for occupant comfort and productivity, with CO₂ levels serving as a key indicator. For facilities managers, keeping CO₂ concentrations in check isn’t just about comfort—it affects health, focus, and energy efficiency. High CO₂ levels often signal poor ventilation, leading to fatigue and reduced cognitive performance.
Categories: HVAC
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Indoor air quality plays a critical role in occupant comfort and productivity—especially when it comes to CO₂ levels. For facilities managers, maintaining optimal indoor air quality is more than a comfort issue—it directly impacts occupant health, productivity, and energy efficiency. One key indicator of indoor air quality is carbon dioxide (CO₂) concentration. Elevated CO₂ levels can cause fatigue, drowsiness, and decreased focus—issues that are often traced back to insufficient ventilation.

Using a Temperature/RH/CO₂ Logger is a practical and powerful tool to support HVAC operation and maintenance. It gives you real-time data to make informed decisions and fine-tune your building’s ventilation strategy.

What is a Temperature/RH/CO₂ Logger?

An Temperature/RH/CO₂ Logger is a device that tracks and logs temperature, humidity, and carbon dioxide levels. It comes equipped with Bluetooth connectivity, allowing for wireless data transfer to a mobile device through an app.

This technology empowers building maintenance teams to oversee essential diagnostics, such as ensuring adequate ventilation in areas like conference rooms or auditoriums.

HOBO Carbon Dioxide/Temp/RH Data Logger.
Source : Onset
Table 2. Ventilation and Resultant CO2 concentration.Source: Heatspring Magazine

Why Facilities Managers Should Monitor CO₂:

  • Ensure Proper Ventilation: Confirm that workspaces are receiving adequate fresh air, improving occupant comfort and safety.
  • Understand Occupancy Trends: Track how spaces are used throughout the day to optimize HVAC scheduling and airflow.
  • Detect Problem Areas: Identify zones that are under- or over-ventilated and adjust air distribution for maximum efficiency.

Benefits of Using an Temperature/RH/CO₂ Logger for HVAC systems

  • Improved indoor air quality monitoring: This logger helps avoid conditions that encourage the growth of bacteria or mold with the ability to monitor temperature and humidity in addition to CO₂ levels.
  • Energy Efficiency Optimization: CO₂ monitoring enables demand-controlled ventilation, which helps the facility manager adjust fresh air intake based on occupancy reducing energy waste.
  • Data Driven Decision Making: The ability to log the data enables trend analysis which leads to improve HVAC operations, and supports facility managers in making informed changes.

You can check out our equipment library to find a Temperature/RH/CO₂ Logger suitable for your application by using the various filters and search functionality. For more guidance on equipment suitable depending on the application, see our measurement guides.