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Millions of Americans have been diagnosed with sleep apnea, a medical condition that causes temporary loss of breath during sleep and is also linked to heavy snoring. The most common forms of this disorder are obstructive sleep apnea (OSA) and central sleep apnea (CSA). While there is currently no cure for sleep apnea, positive air pressure, or PAP, therapy is commonly prescribed to treat the condition. This form of therapy requires an airflow generator (also known as a PAP machine) that draws in outside air using an electric fan, pressurizes and humidifies the air, then delivers it to the user through a connective hose and a nasal or full face mask. Types of PAP therapy include continuous positive air pressure (CPAP), bi-level positive air pressure (BiPAP), and automatic positive air pressure (APAP).
The PAP machine humidifier plays a crucial role during CPAP, BiPAP, or APAP therapy. By adding moisture to the pressurized air, users experience less irritation in their breathing passages and are at lower risk for other side effects of PAP therapy, such as congestion and frequent nosebleeds. Humidifiers may be heated or cold. Additionally, the humidifier may be integrated or built into the machine, or used as a standalone device. Prices for humidifiers vary by model and type, but most cost between $50 and $250.
This guide will explore common designs and functions of PAP humidifiers, compare different types of humidifiers sold today, and provide some buying and maintenance tips for first-time owners.
PAP machines deliver airflow at specific pressurized settings. The pressure of this airflow is measured in centimeters of water (cmH20); most machines offer a pressure range of 4 to 20 cmH20. CPAP machines provide a steady (or continuous) pressure rate throughout the night; BiPAP machines deliver two airflow rates, a higher rate for inhalation and a lower rate for exhalation; and APAP machines deliver a variable pressure rate based on the user’s breathing patterns.
Humidifiers ease the breathing process for sleepers receiving CPAP, BiPAP, or APAP therapy. The airflow from PAP machines can be an irritant, especially at higher pressure settings. Without humidified air, PAP recipients are susceptible to the following:
These issues are particularly commonplace during the early stages of PAP therapy, when sleepers are not yet accustomed to the process. If these problems persist, PAP users are at risk for infections as well.
The following sequence demonstrates how PAP machine humidifiers work:
In terms of design, humidifiers generally fall into one of the following three categories.
The table below illustrates the similarities and differences between the three humidifier types:
|Humidifier Type||Construction||Water Application||Pros||Cons||Average Price Range|
Second hose and power cord not required
|Remove humidifier to fill with water||Small and compact
Fewer parts required
|Incompatible with most machines
Smaller size provides less humidification
|$100 to $200|
Second hose and power cord not required
|Remove chambers to fill with water||Small and compact
Fewer parts required
|Smaller size provides less humidification
Replacement machine needed for humidifier repairs
|$400+ (includes machine)|
|Standalone||Not attached to PAP machine
Second hose and power cord required
|Removal not required||Universal compatibility
Larger size provides more humidification
More parts required
|$120 to $175|
Regardless of whether a humidifier is integrated, built-in, or standalone, most models share the following characteristics:
Please note that a doctor’s prescription is required for all integrated, built-in, and standalone humidifiers. To learn more, please visit our guide to CPAP, BiPAP, and APAP prescription requirements.
Next, we’ll look at key differences between heated and cold PAP humidifiers.
Humidifiers fall into one of two categories based on their temperature settings:
Heated and cold humidifiers may be integrated, built-in, or standalone. The table below looks at some key aspects of both humidifier types.
|Characteristic||Heated Humidifiers||Cold (Passover) Humidifiers|
|Construction||Water chamber with built-in element||Water chamber with no element|
|Customization||Temperature can be adjusted||Temperature cannot be adjusted|
|Average Price||$100 to $250||$50 to $90|
|Battery Life (DC Voltage)||8 hours or less||More than 8 hours|
It’s important to note that heated humidifiers have higher satisfaction ratings among PAP therapy users. Warmer air is more comfortable to breathe in, most say, and users tend to experience less irritation. Those who use cold/passover humidifiers tend to experience more irritation and discomfort by comparison.
Now let’s look at proper care and maintenance guidelines for PAP humidifiers.
Tap water contains a high concentration of hard minerals that can accumulate in the water chamber and eventually damage the machine. Additionally, breathing in these mineral deposits can lead to congestion and has been linked to more serious health problems, such as lung disease. Filtered, distilled water — which has lower concentrations of these minerals — is the best option, but bottled water will also be suitable.
The chamber should be emptied and cleaned in the morning after each use. This will help prevent mineral deposits from forming and extend the humidifier’s overall lifespan. Also be sure to empty the chambers completely before traveling with a humidifier; this will reduce the damage caused by standing water in the chamber; for airline passengers, this also ensures the humidifier will comply with regulations for bringing liquids on board.
As mentioned above, many PAP machines come with built-in rainout reduction systems. However, rainout may still occur even with these systems in place — especially if the humidifier is heated. To minimize the risk of rainout, be sure to do the following:
When shopping for a new CPAP, BiPAP, or APAP machine humidifier and comparing different brands and models, here are a few variables to keep in mind:
Prices for humidifiers vary by construction and temperature settings. Both integrated and standalone humidifiers are usually priced between $100 and $160, while built-in humidifiers come with PAP machines (typically $400 or more). Cold or passover humidifiers tend to be less expensive than heated humidifiers.
Surveys have found that most PAP therapy recipients prefer heated humidifiers because they offer adjustable temperature settings and cause less irritation and discomfort. However, cold/passover humidifiers tend to be priced lower.
Distilled water is needed for all humidifier types in order to prevent mineral buildup and reduce the risk of congestion and other health issues. If you don’t have easy access to distilled water, then bottled water should be used instead — and this may affect your long-term budgeting for the machine.
One notable downside of heated humidifiers is that they tend to drain batteries when the machine is powered with DC voltage. In most cases, the battery will need to be charged daily in order to provide at least eight hours of PAP therapy that night. Using heated PAP hoses also minimizes battery life. If you primarily power your machine with DC voltage or plan to travel with it, then be sure to stock up on batteries and inquire about charging options at your planned destinations.
Most CPAP, BiPAP, and APAP machines are covered under some sort of warranty. The humidifier may be covered under the same warranty, or a separate warranty. Most separate humidifier warranties cover the product against defects for three to five years.