Calculator for air changes per hour

Check a room's estimated air change rate with our calculator

“Air changes per hour” is also called “air exchange rate”, and it refers to the frequency at which a volume of air is either added, extracted, or exchanged within a room.

WindowMaster offers a convenient solution for checking the estimated air change rate in a room. With our free calculator tool, users can easily perform natural ventilation calculations for a specific room. You only need to put in information about:

• Building location
• Height from ground to opening
• Room volume
• Window groups

By putting in the necessary information, such as room volume and orientation of the windows, the calculator will provide an estimate of the air change rate. This rate is determined by the airflow rate multiplied by the room's volume.

Additionally, the tool also displays the air change rate in relation to the temperature difference between the indoor and outdoor environments, indicating the performance based on thermal buoyancy.

The first step to improving poor indoor air quality

Utilising our calculator for air change per hour is the first step towards finding the right natural strategy for a good indoor climate. As this innovative tool allows you to assess the air change rate in a room, it provides valuable insights into the effectiveness of different natural strategies.

By understanding the air change rate, you can make informed decisions on which approach is the most optimal for your specific project. For that reason, the calculator acts as a crucial first step towards creating a healthier indoor climate.

Additionally, this calculator can also help you understand how your current ventilation strategy performs.

Let WindowMaster help you with the indoor climate solution

For more complex calculation requirements, you can reach out to our team of Cleantech Engineers for further assistance. And once the air exchange rate has been determined, we can also assist you in finding the perfect indoor climate solution for your needs.

Whether you require help in choosing the most suitable natural ventilation options or need maintenance services for your existing ventilation system, our dedicated team is ready to offer their expertise.

At WindowMaster, we have an in-depth knowledge of industry trends, state-of-the-art technologies, and sustainable practices, which means that we can help you create a space that combines functionality, aesthetics, as well as environmental responsibility.

PAA

What is a good ventilation air change per hour?
The ideal air change per hour (ACH) depends on the type of room. For school classrooms, a good ACH is typically between 4 and 12 air changes per hour to keep the air fresh and healthy for students and teachers. In restaurants, where there are often more people and cooking smells, the recommended ACH is usually between 8 and 12 air changes per hour. Higher air change rates help improve air quality and create a more comfortable environment.

What are 4 air changes per hour?
Four air changes per hour means that all the air in a room is completely removed and replaced with fresh air four times in one hour. This measurement shows how often the entire volume of air in a space is refreshed, helping to maintain good air quality.

How do you convert air changes per hour to CFM?
To convert air changes per hour (ACH) to CFM (Cubic Feet per Minute), use this formula:

CFM = (Room Volume in cubic feet × ACH) ÷ 60. This tells you how much air needs to be moved each minute to achieve the desired number of air changes per hour in the room.

How do you calculate air change per hour?
To calculate air changes per hour (ACH), use this formula: ACH = (CFM × 60) ÷ Room Volume. Start by finding the airflow rate in Cubic Feet per Minute (CFM), then multiply by 60 to get the hourly airflow. Divide that by the room’s volume in cubic feet. The result is how many times the air in the room is replaced every hour.