When winter comes calling, and the holiday rush kicks into high gear, it can be easy—even in places with relatively mild winters, like Texas—to overlook a small but important detail in home maintenance: replacing our trusty furnace filters.
And while everyone agrees that regular replacement is a great idea, it’s not always easy to know which filter is right for your home and system. So in addition to reminding you to change out your filter every one to three months, we’ve assembled this easy guide to various filter types that you might have, or need, in your home heating system.
Not All Furnace Filters Are Created Equal
In addition to protecting your furnace from contaminants that could damage the system and/or reduce its efficiency, your furnace filter is designed to reduce the amount of dirt and debris that enters the air you and your family are breathing.
The challenge lies in the fact that, the better a filter is at its job, the harder your system has to work. That’s because a filter (particularly high-end ones) slow down airflow. Your furnace filter comes with a MERV (Minimum Efficiency Reporting Value) rating between 1 and 20 (the majority of residential filters fall in the 1-13 range; higher values are generally seen in hospital and commercial applications). A higher MERV rating indicates greater efficiency in removing small airborne particles and contaminants.
So while the department store fiberglass filter might be doing an okay job of filtering out dust bunnies and debris, it isn’t necessarily improving your air quality or providing adequate filtration for those with breathing issues, while a super-high-end filter might be overkill if you’re looking to balance air quality with system performance. Let’s take a quick look at the most common types of filters:
Basic Panel Filters (MERV Rating of 1-4)
These are the common, fiberglass-based, grab-one-at-the-HEB furnace filters we’ve all seen before. They’re inexpensive, disposable, and mostly designed to protect the furnace from dust and particle build-up. A hefty percentage of allergens such as mold, pet dander, and dust mite debris will still make it through these filters, so they’re not great for anyone with pets, allergy sufferers, or heavy smokers sharing their home. Ideally, you’ll change this type of filter monthly.
Extended Surface/Pleated Air Filters (MERV Rating of 5-13)
Pleated to create an increased surface area, these “folded filters” catch more contaminants and filter out particles between five and ten microns, which includes a variety of dust and dander, mold spores, certain bacterias, and even hair spray and auto emissions. Higher-end versions may rival true HEPA (High Efficiency Particulate Air) filters for practical efficiency, without the added complexity and expense installing a HEPA system would entail. They cost a little more, but have to be changed less often, lasting up to three months.
Electrostatic Filters (MERV Rating varies, but comparable to a panel filter or low-end pleated filter)
These filters generate a charge via increased air resistance to attract particles, trapping them. They have the benefit of being washable, which means you, or your tech, will give them a once-over with warm water once a month over their average lifespan of five years, defraying the initially higher cost. The increased maintenance and relatively low efficiency compared to higher-rated panel filters, plus potential headaches such as mold on a neglected filter might make you think twice, however.
Which filter is right for you? A quick consult with your local HVAC pro can help you find out whether your system can handle higher-efficiency filters—or if it might be time for an upgrade. And whichever you choose, remembering to clean or replace your filter on a regular basis can help ensure your family is happy, healthy, and breathing easy all year long.