Furnace Filters That Do Not Reduce Air Flow

Fiberglass Filters

• Fiberglass filters are made of spun glass, much like fiberglass insulation. The air passes through the fiberglass filter, which catch the dust, dirt, and other particles in the air. Fiberglass filters, however, do not collect smaller particles such as pollen or pet dander. For this reason, fiberglass filter have a low MERV rating. The MERV rating is a rating system that classifies filters from 1 to 16, 1 being low quality and 16 being high quality. Fiberglass filters have a MERV rating of 1 to 4. However, fiberglass filters do not restrict air flow as long as they are replaced according to the industry standard of every 3 months.

Media Filter

• Media Filters have an accordion-like appearance, are between 5 and 8 inches thick and comes in a box shape. The accordion design gives the filter more surface area for particles in the air, including pollen and pet dander, to get caught. Media filters are made of polyester material which allows the filters to hold substantial amounts of materials compared to standard pleated filters, meaning the filters can be changed fewer times; about once every 3 to 6 months is the average media filter lifespan. Media pads are also available and need a permanent frame that is typically made out of aluminum or plastic. The frame supports the media filter and the frame generally lasts for the life of the furnace or blower unit.

  The MERV rating for typical media filers is 5 to 8 making them the highest rated and most efficient non-air-flow-reducing filter available.

Electrostatic

• Electrostatic filters are electronically charged aluminum filters that can be washed and should never have to be replaced. This makes the filter the most expensive option, but it will last a lifetime so the costs will actually be less over time than disposable filters. Electrostatic filters work well for typical filtration of dust and larger particles, but perform poorly for pollen and other allergens.

  The MERV rating for electrostatic filters is 1 to 4, and is currently the only non-disposable option available for non-air-flow-restrictive furnace filters.