How Do I Know If My Sleep Test Machine Is Working?

If you wake up feeling just as tired as when you went to bed, your sleep test machine might not be working right. The clearest sign is your AHI (Apnea-Hypopnea Index) number. A working machine should show an AHI below five events per hour. If your AHI stays over five or your sleep quality score does not improve after a week of use, something is off with your device, mask, or settings. You can also check by reviewing your leak rate and looking at your device’s display for error codes.

What Does a Normal AHI Number Look Like on My Machine?

Your AHI number is the most direct measure of whether your sleep test machine is doing its job. AHI stands for Apnea-Hypopnea Index. It counts how many times per hour you stop breathing or breathe shallowly.

For most people with sleep apnea, a working machine should keep AHI under five. Many machines aim for under two. If your AHI is consistently above five, the machine is not treating your apnea effectively.

Check your machine’s screen or app every morning for the first week. Write down the numbers. If you see AHI of ten or higher on multiple nights, your device needs attention. It could be a mask leak, wrong pressure setting, or a machine that needs repair.

Some people have a “bad night” now and then. One high AHI reading is not a crisis. But if the number stays high for three nights in a row, it is time to troubleshoot.

How Do I Check If My Mask Is Leaking Too Much?

Mask leaks are the most common reason sleep test machines do not work well. A large leak means air escapes instead of keeping your airway open. Your machine cannot treat apnea properly when this happens.

Most modern machines report a leak rate. Look for a number measured in liters per minute. For most machines, a leak rate under 24 L/min is acceptable. Above that, your therapy is compromised.

You can also feel for leaks yourself. Run your hand around the edges of your mask while the machine is on. If you feel air escaping, the seal is not tight. Check if your mask straps are too loose or too tight. Both can cause leaks.

Replace your mask cushion every three to six months. The silicone wears out and gets stiff. A worn cushion will leak even if the fit looks fine. This is one of the most overlooked maintenance tasks.

What Should I Look for on the Machine Display or App?

Your sleep test machine gives you several data points every morning. You do not need to be a technician to understand them. Focus on three numbers: AHI, leak rate, and usage hours.

Usage hours matter more than people think. If your machine shows you only used it for two hours, you did not get enough treatment. The machine cannot help if it is not running while you sleep. Many people take their mask off mid-night without realizing it. Check your usage hours each morning.

Some machines also show a “90% pressure” number. This tells you what pressure your body needed for most of the night. If this number is much higher than your prescribed pressure, your settings may need adjustment. Talk to your sleep specialist about this.

Current research suggests that patients who check their machine data daily have better outcomes than those who wait for a doctor visit. The feedback loop works. You catch problems early when you look at the numbers every morning.

What Physical Signs Tell Me the Machine Is Working?

Numbers matter, but how you feel matters too. A working sleep test machine should make you feel different within a few nights to a few weeks.

The most common positive signs include:

• Waking up with less headache or dry mouth
• Feeling less drowsy during afternoon hours
• Not waking up gasping for air
• Your bed partner reports quieter snoring
• Better concentration during the day

If you have been using your machine for two weeks and feel no different, something may be off. Some people take longer to notice benefits. But if you feel exactly the same as before treatment, your machine may not be delivering adequate therapy.

There is a common myth that you should feel “amazing” immediately. That is not how sleep treatment works for most people. Many people feel a gradual improvement over weeks. The real question is whether you feel better than before, not whether you feel perfect.

One non-obvious sign of a working machine is that you stop waking up to use the bathroom at night. Sleep apnea causes frequent nighttime urination in many people. When the machine works, this often improves within a few days.

How Do I Know If the Machine Itself Is Broken?

Machines do break. They are electronic devices with moving parts and filters. The average CPAP machine lasts about five years. After that, the motor can lose accuracy. The pressure delivered may not match what the display says.

Signs your machine hardware may be failing include:

• Strange noises like rattling or whistling that were not there before
• The display screen flickers or shows error messages
• The machine blows very weak air even on high pressure settings
• The machine shuts off randomly during the night
• You smell burning plastic or ozone

If you suspect a hardware problem, do not try to fix it yourself. These machines have internal calibration that only a technician can check. Call your equipment provider or the machine manufacturer. Many offer diagnostic tests over the phone.

Some people report that their machine sounds different after a power surge or after being dropped. Trust your instincts. If the machine sounds or feels wrong, it probably is. As of 2026, most manufacturers recommend a professional recalibration every two years even if the machine seems fine.

What About the Humidifier and Heated Tubing?

Your machine has more than just a blower. The humidifier and heated tubing are part of the system. If these parts fail, the machine may still run but your therapy quality drops.

Check if the humidifier chamber is heating properly. You should see steam or feel warmth when you touch the chamber during operation. If it stays cold, the heating element may be broken. Dry air can cause nosebleeds and throat irritation that makes you stop using the machine.

Heated tubing prevents rainout. Rainout is when water condenses inside the tube and makes gurgling noises. If you hear gurgling, the tube temperature may be too low. Increase the tube temperature setting on your machine. If the problem continues, the heated tubing might need replacement.

These parts are replaceable. You do not need a whole new machine if only the humidifier or tubing is broken. Check with your supplier for compatible replacements.

Frequently Asked Questions