When you first purchase a furnace filter, there is no expiration date while it’s not in use. However, once the filter is installed in your unit and in use, it does have an expiration date of sorts – most filters have a service life between 3 to 4 months. You can refer to the packaging details on when to change the filter or follow recommended guidelines from the furnace manufacturer about how often the filter should be replaced.
A filter becomes clogged after so much use, which requires it to be changed. Your furnace can’t operate efficiently when the filter is dirty, creating performance issues and even system failure. The manufacturer recommends how often your filter should be replaced depending on the filter you have installed.
Typically, filters should be replaced once every 3 or 4 months. If you have a cheap disposable filter, you may need to replace it once every month. More expensive OEM filters can last anywhere from 6 months to a year. If you have pets indoors, smoke in your home, or have remodeling going on in or around your house, the filter will need to be checked regularly and replaced earlier than the average filter.
The best practice when it comes to your filter and its expiration date is to have maintenance performed at least twice a year. Many licensed HVAC dealers offer a preventative maintenance plan for your furnace or other heating and cooling system. A skilled and licensed professional will inspect your unit and determine anything needs replaced or fixed, including the furnace filter. If the filter is clogged or if the system is dirty from the filter failing to do its job, the technician will clean your system during the maintenance call.
If you aren’t sure when you last replaced your filter and don’t know the expiration date, there are a few signs it’s time to change it. If you notice any of the following issues with your furnace or indoor air quality, change the filter immediately or call a professional to replace it for you: