6 Reasons Why Your CPAP Is Blowing Cold Air

CPAP machines blow cold air when the original temperature is set too low, or the room is cold. This problem can also be caused by electrical problems and dirt buildup inside the CPAP.

CPAP therapy is an effective solution for sleep apnea, with the machines releasing a constant supply of pressurized, hot, humid air that makes it easier to breathe. But, a problem in the machine can cause it to start blowing cold air, which makes it harder for you to breathe.

This article explains all the reasons why your CPAP could be blowing cold air and the effect it can have on you. We also discuss some quick troubleshooting tips to fix each problem.

Why CPAP Air Is Heated And Humidified

Before we dig into why your machine could be acting up, it’s important to first understand how a CPAP machine operates when it’s working properly.

  • A powerful motor pulls air into the CPAP system.
  • The air stream passes through a series of filters (antibacterial, reusable, and disposable filters) which trap airborne contaminants.
  • Next, the motor compresses the filtered air to adjust its pressure according to the preset levels.
  • Air is propelled towards a heater and humidifier, which warms the air up, and improves its moisture content.
  • The processed air is finally transmitted through an oxygen pipe and a sealed oxygen mask to the user. Tiny spaces in the mask are used to vent the inhaled air out.

Humidification of the CPAP air stream helps keep the mouth and throat from drying. Since warm air has a higher moisture-holding capacity, CPAP machines come with heated humidifiers.

The setup includes a tank or chamber filled with distilled water. A hot plate usually sits at the base of the tank, which heats the air as it passes through the tank.

Heated humidifiers can be detachable (integrated humidifiers) or built-in (cannot be removed – this means the machine cannot be used without a humidifier). There also is a third type called Passover humidifiers.

Although they can connect to any CPAP device, Passover humidifiers do not allow much humidification.

The Effects Of Cold CPAP Air

Cold CPAP air directly reduces the humidification of the air.

Sleep apnea patients are at higher risk of developing respiratory disorders like allergies, sinus infections, and colds. Patients also often have diseases like asthma and emphysema.

Dry air can exacerbate these conditions, resulting in extreme discomfort.

Rainouts are also a common side-effect of cold CPAP air.

Rainout is when water drips into your nose and/or mouth because of condensation buildup in the mask. A working heater (or heated humidifier) usually maintains the machine temperature within an ideal range of around 60 to 86°F, which prevents rainout.

Cold air, on the other hand, leads to excessive condensation inside the mask, resulting in an uncomfortable rainout.

These problems lead to compliance issues, and can make the CPAP therapy ineffective.

Plentiful Air has more information if you are also concerned that your CPAP is losing pressure available here.

Reasons Why Your CPAP Is Blowing Cold Air

CPAP machines are electronic devices that can start glitching without any serious underlying problem. So before jumping into detailed troublehshooting, follow these more straightforward steps to see if they are a quick fix for your CPAP blowing cold air:

  • Touch the humidifier base, and check if it is hot.
  • If the base does not feel hot to touch, then the CPAP heater is probably acting up.
  • Turn the device off, and disconnect the power cable.
  • Remove the humidifier, and insert it back, ensuring that it is properly secured in place.
  • After a few minutes, plug the machine back in, and turn it on.

If the problem persists, here are the causes you should look for:

1. Settings

Okay, this might seem obvious, but CPAP machines have a setting that determines the temperature of pressurized air emitted from the device.

If the pressurized air feels cold through the mask, you should first check the preset level.

Switch up the level gradually, and see which one you’re comfortable at. It’s also important to mention that air shouldn’t be too hot as it can lose moisture, causing dry mouth and general discomfort.

2. Low Bedroom Temperature

Your room temperature can impact the temperature of your CPAP air. If the bedroom is too cold, your CPAP can start blowing cold air (especially if the machine’s temperature is set to default or a low level).

If you are not comfortable using a heater, insulating hose skins for the CPAP hose can do the trick. These are long, soft, washable covers that cover the device and keep it warm.

Running your CPAP oxygen tube under a blanket while sleeping can also do the trick. Just make sure it isn’t in a position that you can accidentally roll on top of it and stop the flow of air!

3. Broken Heater

If room temperature and settings are not your problem, you need to check if the heater or heating component of the humidifier is working fine.

If the humidifier base feels completely cold upon touching, chances are your heater is not working.

The heater on CPAP machines usually breaks or stop working because of dirty filters or mineral build-up (keep reading for more information on both of these).

4. Dirty Filter

CPAP machines have filters that remove some of the more common airborne contaminants. These filters have a specific capacity beyond which they cannot trap more pollutants.

This means if the filter is not cleaned or replaced on time, it allows dust and debris to pass through with the air stream. These contaminants can build up in any component of the device (like the heater and humidifier) and eventually stop it from working.

This problem can also be identified by reduced air pressure, rainout, and problems in your CPAP data recording.

Cleaning the filters and replacing them regularly can prevent this problem. Here are some general maintenance tips to help prevent dirty filters becoming a problem:

  • Remove the foam (reusable) and paper (disposable) filters and lightly tap them against a solid surface. This helps get rid of dust trapped in the pores.
  • If the filter appears swollen or severely clogged, rinse it with gently running water. You can also use a cleaning solution (1.25-ounce dry powder in 1-gallon water). Make sure to let the filter dry before placing it back in the machine.
  • If the filter appears swollen or requires frequent cleaning, you should change them (4 weeks for foam filters and six months for plastic filters). Note that bacteria filters are non-washable and should be changed directly every four weeks.
  • Your CPAP filters can turn black if you have any devices involving combustion lying around. This happens because of the black powdery substance called soot that is made from heating equipment. Soot buildup can also interfere with filtration, so it is better to avoid candles and furnaces in the same room as CPAP machines.

To improve the air quality and general lifespan of the CPAP filters, you can also consider running a good-quality air purifier in the house.

If you frequently have a black filter in your CPAP, Plentiful Air has more information on how to fix it available here.

5. Minerals From Humidifier

You are supposed to use distilled, demineralized water in the tank. This is regular tap water contains minerals and salts that are left behind as residues as the water is used up for humidification.

Over time, the mineral buildup forms clogs in both the tank and heating plate. This naturally affects the process.

Other than this, residues can also accumulate inside the tubing, reducing the air pressure and flow. This keeps the air in the tubing for a long period of time, allowing it to cool down.

Using demineralized water can save you this trouble. If distilled water is not easily available, you can use demineralization cartridges in the humidifier to absorb the minerals.

Note that it is also important to regularly clean and descale the humidifier. Once a week, detach the humidifier, drain it, and rinse with fresh water. In the case of mineral scales, fill the tank for 15 minutes with a vinegar solution (1:1 part white vinegar and water). The acidic property of vinegar removes all the scales.

6. Electrical Problems

The heating plate works when supplied with enough voltage. Electrical issues like voltage surges can burn the wiring thanks to overheating.

The CPAP machine will keep running if the main power supply is intact; however, the heater can stop working due to damage to its specific wiring.

If you suspect a wiring issue, contact the customer service of your CPAP machine’s company to look into it and fix the problem.

What Temperature Should My CPAP Be Set At?

CPAP manufacturers and physicians recommend 60 to 86°F as the ideal temperature for CPAP tubes.

It’s always best to follow the suggestions of your manufacturer as it normally means your CPAP machine will last longer, and be more effecitve.

Theresa Orr

Theresa Orr holds a PhD in Earth Science and specializes in determining past climates from rocks using geochemistry. Her passion for clean water, soil and air drives her to provide easy to understand information for everyone to read.

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