Indoor Air Quality: Beyond MERV13
O’Dell Associates-Ottawa is committed to offering you solutions to help improve your indoor air quality.
How do I achieve better air quality with my existing HVAC system?
Replacing your main air handling equipment is typically not feasible and adding a HEPA filter to your existing system is not the solution. Most systems are not set up to handle HEPA filters. The static pressure would be too high, the existing filter frames would not be suitable for HEPA filtration and it would be costly.
The solution: Upgrade the MERV rating of you existing filters and adding Supplemental filtration. This can be achieved by using a portable or fixed air cleaner.
Air changes per hour is an important measurement for gauging how effective indoor air is exchanged or filtered. Many regulatory bodies recommend specific ACH rates for various types of facilities to ensure enough air is exchanged for optimal air quality. For proper air filtration, a space needs 4 – 6 ACH.
|Ideal (6 ACH)|
|Excellent (5-6 ACH)|
|Good (4-5 ACH)|
|Bare minimum (3-4)|
Low (<3 ACH)
To calculate Air Changes Per Hour (ACH), find the CFM of your device and multiply that by 60 then divide that total by the total cubic feet of the room to get your total ACH.
ACH = CFM x 60 / (Area x Height)
When choosing an air cleaner, you should also consider the following:
- Size – you want to make sure the unit is right for the space intended. (Usually indicated by square feet).
- Airflow (CADR) – Air purifiers with higher CADR ratings will be able to clean the air in a space more quickly than models with a lower CADR rating.
- Filter efficiency – Air cleaner should be designated a HEPA unit, or specifically indicates that it filters particles in the 0.1-1 um size range.
- Sound – some units can be as low as 15 dBA and as high as 75 dBA.