The Impact of Carbon Filters on Airflow

When selecting a fan to meet the airflow requirements of a space, it is important to take into account the resistance to airflow caused by a carbon filter. This resistance can reduce the CFM (cubic feet per minute) by 10-25%. The thousands of pores in the filter are responsible for this decrease, and over time, the prefilter can become clogged and reduce indoor airflow. The main purpose of carbon filters is to eliminate odors from the air. This is because they are made of carbon-impregnated material, rather than electrostatically charged filter material.

The activated carbon filter medium blocks odors and vapors at the molecular level by using valence electrons. Carbon filters also connect at the molecular level with aromas, vapors and gases to prevent them from passing through air ducts. When air passes through a filter, it needs sufficient time to interact with the filter and remove contaminants. A hybrid air purifier or finer filter medium can increase the reduction in airflow. Carbon filters are often found in furnaces and air conditioning systems, where they trap contaminants and allow clean air to recirculate in the room. The CFM value is reduced by 10-25% due to the exhaust fan's resistance to airflow when drawing air through the carbon filter.

The modification process consists mainly of injecting steam or hot air into the charcoal (oxygen), creating millions of tiny pores between the carbon atoms. The size, diameter, and type of connector or duct can also affect the resistance of the carbon filter to the fan's performance in extracting air. A grow room exhaust fan causes all air to pass through the filter, trapping contaminants in the carbon filter. Fan size and CFM are essential values to know if you're using a carbon filter. If odor control is a priority, then carbon filters are an ideal choice.