Air filter efficiencies; upgrading has benefits and pitfalls

There are many guidelines to follow when upgrading air filters for protection against harmful indoor pollutants. Certain restraints may complicate upgrading of air filters, such as the new filter making an exact fit without modification, and the pressure drop not being more than the existing system can handle. The cost of upgrading your filter should not be excessive, and should not require new equipment or different service skills to maintain.
Publicity about building-related illness and sick building syndrome has created a demand for air filters that give adequate protection against dirt buildup on coils and in duckwork, and also provide [...]