It is up to the customer to make decisions such as which filter to buy, how many to install, and where to install. We are not responsible for misuse of our products. But, with our testing and research we have some recommendations for the most practical and safe use of these filters in your application.
Where to Install
The AIROTRUST 2x2 magnetically attaches to any air vent (supply or cold air return) that sits inside of a 2'x2' ceiling tile. These types of air vents are very popular especially in office buildings and small businesses.
There are a few different approaches you can take when installing your AIROTRUST units. One of the ways we recommend installing this unit is on the cold air return vents only. When you install an AIROTRUST unit with a Camfill filter to a cold air return vent, you are pre-filtering the air before it is send back to the HVAC unit where it is again filtered by your furnace filter. This method is great when targeting air quality needs to certain areas is not as important as improving overall air quality. Note: this method is the safest for your HVAC system if you have an ECM motor that will ramp up its speed to make up for the increased air restriction.
Another way we recommend, is placing the AIROTRUST unit on supply vents which can be perfect for small businesses. This is a good way to target the specific needs of an individual or area of your building. This can ensure your customer or employee that the air blowing out of the vents directly towards them has an extra layer of safety.
A main concern that customers face when installing an air filter directly to your system at the ceiling is the added airflow restriction of these filters. Many are worried that with the added airflow restriction, the evaporation coils on their AC unit would freeze. Our findings, that have been backed up by an HVAC testing company, have determined that most modern HVAC motors are ECM (Electronically Controlled Motor) allowing the motor to automatically run faster when it detects a restriction in airflow. With an ECM motor, our testing showed that the airflow over the coils is nearly the same with and without our most restrictive filters covering all of the cold air return vents. Even without an ECM, we would like to point out that AIROTRUST was not designed to be a permanent air quality solution. We recommend using this product temporarily during flu and allergy seasons. Furthermore, choosing one of Camfill's least restrictive, yet effective, filters such as the 30/30 dual 9 would be a great choice for anyone with airflow concerns. Also, choosing a thicker 4" filter (when the vent/diffuser leaves enough room for it) makes the filter much less restrictive by increasing the surface area of the filter while retaining the filtration efficiency.
How to Choose the best filter for your application