When used regularly, your furnace will over a period of time collect a lot of air pollutants such as dust, animal dander and pollen. All of these can be harmful to family members, especially those who are more prone to suffering from allergies or any other respiratory problems. The best furnace filters effectively trap these particles and help maintain the quality of the air in the home.

Types of Furnace Filters

There are basically two types of furnace filters for domestic use: Disposable and Permanent. The third type, HEPA filters are recommended for industrial use only.

Disposable Furnace Filters – Designed to trap only large dirt and dust particles, these are the least expensive types of air filters but they are also the least effective in cleaning and filtering the air in the home. The cost could add up quickly as they would need to be replaced every 1-3 months, depending upon your usage. Disposable air filters come in two varieties:

• Fiberglass air filters: These are typically made from dense fiberglass or other man-made materials to get the best filtration. The fiberglass is bonded thermally between two sturdy metal grids, which make it more rigid.
• Odor-relief filters: These filters typically have a pleated design, which provides a larger surface area for capturing air pollutants, fumes and odors such as those emitted from food, cigarettes, pets or mold. The odor is trapped using an active carbon medium.

Permanent Furnace Filters – Designed to be permanently installed, these filters are considerably more efficient than their disposable counterparts. They need to be washed regularly to maintain efficient air filtration.  The most common permanent furnace filters are the pleated and the electrostatic filters.

• Pleated Furnace Filters: These typically feature fabric pleats that increase the surface area. They have a denser mesh material and help eliminate larger sized allergens such as mold and pollen.  They have a 35-50% efficiency level.

• Electrostatic Furnace Filters:  Electrostatic filters work on the principle of static electricity. The filter’s static charge ‘magnetizes’ airborne pollutant particles, which then accumulate on the filter material. These filters are considered the most efficient.

HEPA Furnace Filters – Short for High Efficiency Particular Air, HEPA filters eliminate up to 90% of all dust particles and allergens and are used in research centers, manufacturing plants and hospitals where it is crucial to maintain the highest quality of air. However, they are not the first choice for home use because, while they are the most efficient, they also significantly impede the flow of air, making the filter work harder and more prone to breaking down.

How Often Should Furnace Filters Be Changed?

How often you need to change the filter of your furnace will depend upon the furnace that you use as well as the types of filters you use.

• Disposable fiberglass filters will need to be changed approximately every 1 to 2 months.
• Washable electrostatic filters need to be cleaned out once a month and changed after about 6 to 12 months.
• Pleated allergy filters typically last a minimum of 3 months but need to be checked regularly for buildup and changed earlier if need be, especially during high pollen season.

Choosing the Best Furnace Filter Size for You

There is no one-size-fits-all when it comes to furnace air filters. Getting the correct size is key to guaranteeing the furnace performs its job effectively to keep the temperature and air quality in your home at optimum levels. These filters come in a wide range of sizes and the best one for you will depend upon the size and design of your house.

How do you determine what will work best for you? Avoid the temptation to do guess work or to round off measurements as you could end up with a filter that will not fit onto your furnace or will just not work as efficiently as you’d like.  When in doubt, ask experts in this sector for their advice on how to determine this important aspect of buying the right furnace filter.