Use it to compare pleated filters and electronic air cleaners. Thermal DOP Efficiency applies to the very highest efficiency filters, such as HEPA filters. Thermal DOP efficiency is tested according to U.S. Military Standard 282. Medium-efficiency are between 30 and 50 percent. High-efficiency are between 50 and 95 percent.
Higher efficiency is usually better, but it can get complicated.
Filters with 95 percent arrestance may catch almost all the lint, but few if any of the smaller particles. Resistance to Air Flow Placing any filter in the air stream increases resistance and reduces flow. This is an important consideration for designing a forced air distribution system. Electronic air cleaners offer relatively low resistance. That's one reason for their popularity.