Why CO₂, Humidity, and Temperature Monitoring Indoors Is Essential in 2025

If you’ve ever felt tired in the middle of the day, struggled to focus during a meeting, or woken up with a dry throat—your indoor environment could be the reason. In 2025, three simple but critical factors have taken the spotlight when it comes to indoor air quality: carbon dioxide (CO₂), humidity, and temperature.

Across Europe, the UK, the US, and the UAE, governments, schools, and homes are taking these factors seriously—and so should you. Here’s why.

CO₂: The Invisible Concentration Killer

While CO₂ is naturally present in the air we breathe, it becomes problematic indoors, where ventilation is often limited. Concentrations above 1000 parts per million (ppm) are associated with reduced cognitive performance, slower decision-making, and increased fatigue (Satish et al., 2012). These effects are most noticeable in tightly sealed spaces—like apartments, offices, and classrooms.

Across Europe, especially in Germany, schools and workplaces have begun integrating CO₂ monitors as part of long-term indoor air quality strategies. The idea of “Lüften” (airing out rooms) remains culturally strong, but sensors now guide when and how long ventilation is needed.

In the US and UK, public interest in indoor air quality spiked post-COVID, especially among remote workers looking to optimize their home workspaces. Google Trends data shows a consistent rise in searches for CO2 monitor indoor and safe CO2 levels at home (Google Trends, 2025).

Meanwhile, in the UAE, where buildings are designed to be airtight to maintain indoor cooling, CO₂ can climb quickly during meetings or overnight without proper ventilation. Many modern buildings now include smart sensors for real-time tracking.

Humidity: The Overlooked Driver of Discomfort and Disease

Humidity may not get as much attention as CO₂, but it has a profound impact on our bodies and our homes. According to ASHRAE (2023), the ideal indoor humidity range is between 40% and 60%. Falling below or rising above this threshold can lead to multiple issues:

• Below 30%: dry skin, sore throats, and static electricity

• Above 60%: mold growth, dust mites, and worsened asthma symptoms

In Northern Europe, winter heating systems often cause indoor air to become too dry, especially in homes with little natural ventilation. In contrast, homes in the UK and parts of the US, particularly older buildings, often struggle with excess humidity—leading to condensation on windows, damp basements, and persistent musty odors.

In the UAE, powerful HVAC systems cool and dehumidify the air aggressively, sometimes creating overly dry environments that irritate the respiratory tract.

Temperature: Not Just a Matter of Preference

We all know when a room feels too hot or too cold—but what many people don’t realize is that indoor temperature can directly influence cognitive function, sleep quality, and energy efficiency.

For optimal focus and work performance, indoor temperatures should stay around 20–22°C, while for restful sleep, the sweet spot is 18–20°C (Lan et al., 2021). Anything consistently outside this range can lead to poor concentration and sleep disturbance. 

To avoid these problems, you should monitor air quality. 
Track key measurements like CO₂, humidity, and temperature—and improve your well-being every day!