How Often Should I Change My Filters? Why Is It Important To Change Them?
By Mark Jackson
The filter on your furnace serves two purposes? It filters particulates in your home’s air to protect your family. The filter also keeps contaminants from damaging the efficiency and effectiveness of your furnace operation. Did you know that because of things such as dust, pet hair, pollen, and volatile organic chemicals in carpeting, paint, and cleaning agents the air inside your home can be as much as 5 times as dirty as the air outside the house. The only thing protecting you is that little 1” filter down at the furnace location.
When you are standing in the filter aisle at the local home center the task of deciding which filter to buy can be pretty daunting. Let’s try to help you out a little. Here is my first rule of thumb; if you can see through the filter, don’t buy it. That filter will do nothing to protect the health of your family, and very little to protect the life of your equipment. To help you a little more, let me introduce to my buddy MERV. Filter efficiency MERV, which stands for Minimum Efficiency Reporting Value, is a rating that was developed by ASHRAE (the American Society of Heating, Refrigerating, and Air-Conditioning Engineers), and it is used to assess the filtering power of an air conditioner or furnace filter.
The MERV scale consists of ratings from 1 to 16, with filter performance being greater as the number increases. On the MERV scale, dirt particles are graded from 0.3 microns to 10 microns. A micron is 1 millionth of a millimeter, and just to give you an idea of just how small that is, you can look at the size of a single human hair. The average strand of human hair is about 100 microns thick, so imagine just how small 0.3 microns of dirt is! Why is MERV Rating Important?
While all filters will provide you with the filtering efficiency needed to improve the air quality of your home, depending on the particular needs of your family, you may require a filter that has a higher MERV rating. Cases in which this is likely are those when you or someone in your home suffers from allergies, respiratory problems, or other similar incidences. Then again, you may just want to get the best filter for your family so that the indoor air quality around your home is the best it can be.
Often the filter will have a recommended change cycle on it. Usually, the higher the MERV rating, the longer the cycle between changes, but this isn’t always the case. High activity homes with pets and children may require more frequent filter changes. Visual inspection of the filter is the best method for determining if it’s time to change the filter. Write the date of the filter change on the filter. Then, when you inspect the filter, you begin a to get a feeling for when it is best to change to a new filter.