What is a Furnace Filter? What does it do?

Often overlooked for its simplicity, but of utmost importance to your heating system is the furnace filter. The purpose of the filter is to keep dust, dirt, and particles from entering into the workings of the furnace motor. As an additional but unintended function, it also removes allergens and dust from the home living environment making cleaner air to breathe. Climate Change recommends changing the furnace filter monthly to assure optimized performance and a clean living environment.

There are many different types of filters. Filters are often rated on a MERV rating scale. MERV stands for minimum efficiency reporting value and has a scale from 1 to 16 with 1 being the least efficient and 16 being the most efficient.

The most common and inexpensive type of furnace filter is usually made of pleated polyester and paper and have a MERV rating of 6. While providing fairly good efficiency, this type of filter is disposable and should not be used more than a month as it can begin to disintegrate.

A lesser efficient type of filter is the disposable fiberglass filter. It only carries a MERV rating on 2 or 3 but can be a very inexpensive option for renters or for people with no allergy issues.

A washable and reusable option for a filter is the permanent electrostatic filter. The electrostatic filter uses self-charging electrostatic cotton to attract particles to it. This type of filter lasts up to 8 years and should be washed monthly to allow optimum efficiency. There also exists a disposable version of the electrostatic filter which can be a great option for homes with pets or smokers. The downside is that it runs more expensive than the pleated or fiberglass filter types. Both the disposable and the permanent electrostatic filters carry a MERV rating of 10.

Typically filters ranking at the higher end of the scale are reserved for hospitals and clinics because they remove the smallest molecules of environmental pollutants. These filters have MERV ratings of 14-16 and are made of a pleated synthetic cotton that is 4 to 5 inches thick. high-efficiency particulate air (HEPA)

People often ask to have an HEPA (high-efficiency particulate air) filter installed on their furnace. This can require a modification to allow the system to work in the same manner and recent studies have shown that there is minimal reduction in allergens with an HEPA filter over a standard MERV rated filter.

The choice of furnace filter to use is a personal one to some extent. Climate Change can help make certain that your system functions properly with the filter of your desire, based upon your needs and lifestyle.