You should know, that most heating/cooling systems in the residential and light commercial markets are designed to move 900 Cubic Feet per Minute (CFM) to 2000 CFM at a total system static pressure of approximately .5" to .7" water column (w.c.) pressure; the total pressure drop including the resistance through the ductwork and the filter.
By design air filters will create resistance to flow and a high differential pressure drop will exist across the filter. Most air filter manufacturers literature suggests replacement of the filter media when the resistance due to contamination loading reaches 2"w.c. pressure or higher.
So, if you put a filter with a higher resistance in the unit than the motor horsepower can handle, you will slow down the heating/cooling blower/motor and reduce the overall effectiveness of the system. This is why all the filters that come with heating/cooling systems as original equipment are the least efficient, low resistance filters.
There is a relationship between filter efficiency and pressure drop and resistance. As the filters become more efficient the final resistance becomes greater.
If you have any questions, please donít hesitate to contact us.