Intro
The virtual sensor Air Exchange Rate (AER) estimates how often indoor air is replaced with outdoor air per hour, measured in air changes per hour (ACH). This metric indicates a building's ventilation efficiency.
Monitoring the Air Exchange Rate is important for:
Indoor Air Quality (IAQ): Higher air exchange rates typically indicate better ventilation, which helps improve IAQ.
Energy Efficiency: While ventilation is essential, it must be balanced with energy efficiency. AER analysis allows for optimizing ventilation systems, reducing energy use.
Regulatory Compliance: Many building codes and standards specify minimum ventilation requirements that AER can help meet.
Virtual sensor
In Dashboard
This sensor is located at the end of the row alongside other virtual sensors. To access it, scroll to the right using the arrow. The data is available for any device equipped with a CO2 sensor.
The black line shows the Air Changes per Hour (ACH)
The transparent areas indicate the min-max within the hour
In API
The API includes the virtual sensor Air Exchange Rate. Once room information is provided, you can also access the virtual sensor Airflow, indicating the volume of air replaced and expressed in m³/h.
Sensor algorithm
The Air Exchange Rate is only calculated when people are in the room. The algorithm is based on current and historic data, and will be more accurate over time. The more data it can register, the more accurate it will be.
The algorithm achieves optimal accuracy in rooms equipped with mechanical ventilation. While it can also detect natural ventilation, such as opening a window or door, the sensor's precision is diminished in such cases.
The algorithm to detect the Air Exchange Rate is trained on the data of many rooms and buildings.
It creates a calendar when the ventilation has run or not, with the use of the building opening hours as a fallback
The algorithm maintains a historic ventilation calendar based on historic detected ventilation and entered building opening hours. It estimates the ventilation rate from historic and current IAQ data both in the different parts of the historic calendar.