A question many people have is how often should their furnace filter be changed? The answer to this question is actually fairly complex. For ages, heating professionals recommended inspecting and usually changing your filter once per month. This used to be important because filters back then were not as sophisticated as they are today. In fact, many of them did little to prevent small particles from circulating through the system because they were designed to block larger particles that could harm the furnace.
Thankfully filters are much better designed these days. Most HVAC professionals now recommend using a high efficiency pleated filter. Some of these have a built in electrostatic charge to better trap dirt and particles. The folds increase the surface area of the filter and the material is better so air flows through more efficiently. The electrostatic charge, which is similar to static cling that you may notice that occurs in your clothes dryer works like a magnet to grab smaller particles, such as bacteria, particles that carry viruses, and the soot in smoke.
The switch to better designed, higher efficiency filters means that professionals now recommended changing them every three months, rather than monthly. They do still recommend inspecting them each month. If your filter is dark and clogged, it’s best to replace it. Air quality differs greatly from home to home; your habits are not the same as your neighbors. If you live with pets or a smoker you will need to change your filter more often.
Based on these issues, you can see that it’s best to switch to high efficiency filters if you’re still using the older styles. The trouble occurs when people switch and then neglect inspections and replacement schedules. With an old style filter, if you forget to replace it for a month, no significant air flow issues will occur, your air quality won’t be as good but the system will continue to work fine.
With high efficiency filters, if you forget to replace it, your system will pay for it. Once they get a little clogged, these filters drastically restrict airflow, causing your furnace to work harder to keep your home comfortable.
If you are the sort who forgets or procrastinates on household chores, sticking with the lower efficiency filter might actually be a better option. If you leave your high efficiency filter in for six months you could be adding hundreds of dollars to your heating bill and wasting a lot of energy, not to mention drastically lowering the air quality in your home. Take your habits into account when buying your filters – if you use the older ones, try to change them every month.