A good rule of thumb is to replace pleated filters every 90 days. If you have electrostatic or washable filters, you should wash, dry and reinstall them once a month. Washable filters are more environmentally friendly and, if properly cleaned and reused, can last 5 to 10 years. You should change most models at least every six months. However, filter quality, allergies, or the presence of children and pets may require more frequent maintenance.
In general, most air filter manufacturers and HVAC companies recommend changing your air filter every 90 days or 3 months. That may change depending on the location of your home (e.g. dry and dusty climates), if you have pets and the age of your system and equipment. If you have pets in the house, you should consider changing the filter every 60 days or 2 months, and for households with multiple pets or people with allergies or respiratory conditions, we recommend changing the filter every 20-45 days. Usually, vacation homes or vacant homes that don't have much use can expect to change filters every 9-12 months.
The general consensus is that the more you use your home, the more you need to change the air filter. An HVAC filter will only last one to three months on average. Which means you need to keep track of the date you installed them. If you wait too long to change the filter, indoor air quality will suffer. We are going to explore each of these factors. This is by far the most important factor.
The filter collects dust and debris only when the system is operating. The more it works, the faster the filter picks up dirt. During a bitter cold Minnesota winter, a furnace filter will need to be changed more often than during a mild Missouri winter. On the other hand, you will need to change the filter more frequently during a hot and humid Missouri summer than during the Minnesota summer. Remember that a filter also gets dirty during AC mode.
Do you find pet hair in your oven filter? Hair fibers from dogs, cats, rabbits and other mammals are large compared to dust and dirt that normally trap the filter. That means they clog the filter and block the airflow pretty quickly. The more important clean air is, the more often the filter needs to be cleaned or changed. A coarse-media filter, MERV 11 or higher, or an electronic air filter is the best option when someone in the household has asthma, severe allergies, or difficulty breathing for any reason. The air will be cleaner than if a basic fiberglass air filter is used.
You may also want to consider an air cleaner for your system. Our Air Purifier Guide contains comprehensive information on all types, including electronic and media air filters, how they work, which is best for your purpose, and more. Cheap fiberglass filters require less frequent replacement than pleated filters. Some sites get this exactly the other way around, claiming that thicker filters can last longer between changes. That goes against the design of the filters. Coarse-media filters trap more and smaller dust particles, so they obviously clog up faster.
Slim fiberglass filters don't trap as much dirt and debris, so they don't clog up as quickly. The good news is that some of those filters can be cleaned with a nylon brush and placed back in the oven or air controller instead of replacing them. Cleaning should be done outside or in a garage to keep dust and dirt out of your home. If removing dirt with a brush instead of replacing the media filter, be sure to change the filter after two or three cleanings. In the end, brush cleaning will not remove enough deeply embedded dirt and debris.
In larger homes, more air flows through the filter than in smaller houses. Because the air carries dust, pet hair, and other debris, the filter will get dirty more quickly in a system that serves a large house. Some of you wonder what we mean by continuous fan mode and why a homeowner would use it. There must be a setting in the thermostat, such as Auto and Fan options. In automatic mode, the fan works only when the system is heating or conditioning the air in your home.
In fan mode it works all the time until you turn it off. The longer the system works, even if it is not heating or air conditioning, the faster the filter will get dirty and it will need to be changed. Is continuous fan mode a good idea? Here are the pros and cons. First, clean the air by passing it through the air filter more often. As a result, it will be necessary to change the filter more frequently. Second, it helps balance temperatures in your home.
Thirdly, if you have a basement you can draw cool air from there to help cool upstairs rooms; however running fans requires electricity so your electricity bill will increase as well as humidity levels in your home due to drawing cool air from basements which can make you uncomfortable in summer so you'll need to lower thermostat settings which causes ACs to work longer resulting in higher electricity costs. In summary we do not recommend continuous fan mode as standard operating procedure. This is real question isn't it? This question gets to heart of matter; follow these steps to find out when to change your air filter: You may hear little wheezing even when filter is clean; it will worsen when filter is dirty; know your system & sounds it emits; check for dust build up on vents & registers; check for dust build up on return grills; check for dust build up on blower wheel & motor; check for dust build up on evaporator coil; check for dust build up on condenser coil; check for dust build up on furnace cabinet; check for dust build up on heat exchanger; check for dust build up on plenum & ducts; check for dust build up on supply registers & grills; check for dust build up on humidifier pad & tray; check for dust build up on UV light bulb & reflector; check for dust build up on electronic air cleaner cell & grid; check for dust build up on media cabinet & blower wheel; check for dust build up on media pleats & frame.