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CPAP filters are the components of a CPAP device that prevent a person from inhaling harmful particles that may be present in their sleep environment. There are three types of CPAP filters, each designed to target different particles.
Knowing about CPAP filters can help you protect your health and maintain your CPAP machine. We cover the different types of CPAP filters, their replacement schedules, and strategies for selecting the right models.
Filters play an important role in protecting a continuous positive airway pressure (CPAP) user’s health. These filters allow a person to inhale clean air through the machine, which defends against lung irritation and limits exposure to allergens.
CPAP machines draw air from the sleep environment. This air may contain:
The filters in a CPAP machine are designed to remove these unwanted particles from the air before pumping it into the CPAP mask. Some CPAP filters are even designed to protect users from inhaling bacteria and viruses such as the flu and the common cold.
CPAP machines may contain both a reusable and a disposable filter, although many machine models require just one type. These filters are often located at the back or on the side of a CPAP machine and may be layered so that air first passes through the reusable filter and then the disposable filter.
A third, optional type of filter is an in-line bacteria filter, sometimes called a bacterial viral filter. In-line bacteria filters tend to connect to one end of the CPAP machine’s tubing. Each of these filter types serves a specific purpose and must be cared for in a particular way.
Reusable filters, also sometimes called non-disposable filters, are designed to be used many times before disposal and replacement. These small, rectangular filters are made of foam. They trap large particles, such as pollen and dust, as air passes through them.
There are several recommendations regarding the care and cleaning of reusable filters, which should take place once a week.
Regularly cleaning your reusable filter can help it last longer and work as intended. Some reusable filters may have additional or different care instructions, so make sure to review the manufacturer's directions before cleaning your reusable filter.
Disposable or fine filters are designed to capture small particles, such as tobacco smoke. They are usually made with fine mesh paper. As their name suggests, disposable filters must be replaced regularly. They cannot be washed, and over a series of uses, they become discolored. When this happens, it’s time to change the filter.
Care for disposable filters is straightforward: Change the filter every 30 days or as soon as the paper has become discolored. As with reusable filters, make sure to unplug your CPAP machine before changing the filter.
In-line bacteria filters are an optional addition for many CPAP machines. These filters trap very small particles that might not be blocked by other filter types, including bacteria and viruses.
Some manufacturers recommend that these filters be used on shared or rented CPAP devices. People who use CPAP devices with humidifiers may also benefit from these filters, as bacteria can grow in humidifier chambers.
Made of fine paper, in-line bacteria filters are typically encased in a hard plastic ball with connection points on both sides. Depending on the machine model and filter design, an in-line bacteria filter may be placed in one of several locations:
While most CPAP machines are compatible with in-line bacteria filters, use of these filters may result in a lower air pressure than your healthcare provider has prescribed. Some machines have a setting called “AB Filter” to make up for the decrease in pressure and ensure you receive the appropriate treatment.
When using a bacteria filter on your CPAP machine, keep the following care instructions in mind.
Properly caring for CPAP filters and replacing them on schedule can help you avoid inhaling irritants or harmful bacteria. Some machines will indicate on their displays when it is time to replace a filter. However, these are usually scheduled reminders and not real-time assessments of filter performance.
The right time to replace a CPAP machine filter depends on the filter brand and filter condition. Several factors can affect the condition of a filter.
If your sleep environment contains any of these potential irritants, or if your CPAP machine has a humidifier, make sure to check the filters on your CPAP machine each week for dirt, damage, and discoloration.
Also be sure to consult the manufacturer’s guidelines for both your CPAP machine and your filters to confirm the appropriate replacement schedule for the products you use.
The steps for replacing a CPAP filter vary among filter types and CPAP machine models. In all cases, you should unplug the CPAP machine before changing any filters.
Generally, you can remove a reusable or disposable filter from its position at the back of the machine or behind a filter door. Then you can install a new filter. If your machine uses both filter types, you may need to snap them together or stack them before insertion.
To replace an in-line bacteria filter, remove the old filter from its position along the CPAP hose. Then, install the new filter by attaching it at the proper connection points.
Make sure to review the manufacturer’s guidelines for replacing your CPAP filters, as machine designs vary.
The requirements of your CPAP device, your sleep environment, and your budget may all influence the CPAP filter you choose. You can also talk with your healthcare provider to identify what CPAP device and filters are right for your treatment needs.
To ensure proper therapy, be sure to follow the guidelines that come with your CPAP machine regarding filters. For example, some manufacturers advise against using in-line bacteria filters with their devices because they can decrease the air pressure received by the user.
Some CPAP devices require either a reusable filter or a disposable filter, while other models accommodate both. The manufacturer’s guidelines for your device identify which filter styles and brands are compatible with the device. Filter manufacturers may also provide a list of compatible devices.
Because the three filter types target different sizes and types of air particles, you may consider your sleep environment in addition to your health needs when deciding which filters to purchase. Reusable filters capture larger particles, disposable filters target smaller irritants, and in-line bacteria filters intercept microscopic germs and allergens.
Health insurance providers or programs such as Medicare may cover some or all of the cost of replacement CPAP filters. Medicare covers two disposable filter replacements per month and a reusable filter replacement every six months. However, some insurers may not cover both filter types.
Bacteria filters are typically not covered by insurance. These filters cost around $3 to $5 each and must be replaced at least monthly.
Allyson is a freelance writer and editor as well as an educator based in Norway. She has a master’s degree in creative writing and a certificate in professional and technical communication from the University of South Florida. She is a teaching assistant for Communication for Engineers at the Norwegian University of Science and Technology and was previously a Fulbright English teaching assistant grantee in Norway. Allyson is passionate about empowering people to take care of their health and get a good night’s sleep.
Gerard J. Meskill, MD is board certified in both neurology and sleep medicine, and he is the founder and CEO of Tricoastal Narcolepsy and Sleep Disorders Center. The “Tricoastal” moniker references his background: he completed neurology residency on the East Coast at Long Island Jewish Medical Center – where he served as chief resident, sleep fellowship on the West Coast at Stanford University, and he now practices sleep medicine and neurology on the Gulf Coast in the greater Houston, Texas area.
