If all you get from this post is a friendly reminder to clean your permanent furnace filter, then I will have done my job. Permanent furnace filters still need cleaning and it’s way too easy to forget since they don’t need physically changing. I often forget to do the cleaning, but I’ll say it again, a permanent filters does not mean no cleaning.
How often do I need to clean my furnace filters?
It’s not as easy a question as you might think. We have permanent furnace filters both at home and office. Our home furnace filters only seems to need cleaning every 3-4 months because it’s located in a suburb of Boston. We’ve found the best way to clean our filters is to take it outside and run the garden hose over it until it runs clean. Given the environment in which we live, the color of the water is usually not noticeably dirty. We let the furnace filter dry completely before reinstalling it.
Our office, located in another part of Boston is another matter. Every time we clean out the permanent furnace filters located on the roof, we get a sharp reminder of how these filters are doing their job. When we clean the furnace filters at work, we spray a non-toxic spray cleaner on both sides of the filter. We then rinse each side with a garden hose, until there is no evidence of dirt by looking at the color of the water. Initially, the water is black but it eventually becomes clear. We then allow the filters to dry thoroughly. You can expedite the drying by setting the filters in the sun or by running a fan on them. Once they are completely dry we reinstall them. The recommendation in general, is to clean your furnace filters roughly every 2 to 4 months depending on the pollution level of the area you live in.
In our case, every 2 months is needed. The importance of cleaning your furnace filters is mainly twofold. The first is to prevent any loss of airflow in your central air system. The second, is electrostatic filters rely on their ability to attract the particulates by their opposite charge which will diminish as more and more covered with particulates. The biggest reduction in efficiency will be for the smaller particulates, because the larger ones will have a better chance of being captured by the filter’s surface area because they are large enough to not pass through the filter.