If you've been using CPAP or BiPAP therapy for any length of time, you've probably realised that your device collects a remarkable amount of data every night. AHI, flow limitation, leak rates, RERAs — it's all there on your SD card or in your device's memory, waiting to be read. The question is: which free CPAP data analysis software should you use?
There's no single right answer. After spending time with all three main tools — OSCAR, SleepHQ, and AirwayLab — my honest take is that they each occupy a different niche. Here is what each one actually does well, and where it stops.
Here's a practical comparison of what each one does well, where it has limits, and how they fit together for a PAP user who actually wants to understand their therapy data.
Why bother analysing your CPAP data at all?
Before comparing tools, a quick word on why this matters. Your device's own display typically shows you a nightly AHI number and maybe a therapy score — but that's a tiny fraction of what's recorded. Understanding your CPAP data means you can see patterns across weeks, see patterns like flow limitation levels or leak rate trends, and have much more informed conversations with your clinician.
None of these tools replace clinical judgement. All three are data exploration and visualisation tools. But having your data in a readable format changes the quality of the conversation you can have with your sleep team.
OSCAR
OSCAR (Open Source CPAP Analysis Reporter) has been part of the PAP community for years, and it browses and reviews CPAP waveforms well. It runs on your desktop, reads directly from your SD card, and keeps everything local. If you're on a forum like CPAPtalk or r/CPAP, OSCAR screenshots are the shared language — almost every active PAP user in those communities knows their way around an OSCAR chart.
OSCAR's depth is its strength and its learning curve. The chart layout is dense and powerful. You can zoom into individual breathing cycles, overlay multiple metrics, and dig into the waveform data that most people never see. If you want to understand how to read OSCAR CPAP charts, that depth pays off over time.
The limitation is friction. Installing OSCAR, getting your SD card into your computer, and making sense of the default view takes effort — especially for new users. On mobile, it's not really an option.
Summary
Detailed waveform inspection on the desktop, and the format the PAP community shares screenshots in.
SleepHQ
SleepHQ is a web-based platform that takes a different approach: you upload your CPAP data to their servers and get back clean, shareable dashboards. The interface is polished, the charts are modern, and the clinician-sharing features are genuinely useful if your sleep team is open to reviewing data between appointments.
The trade-off is privacy. Your therapy data lives on SleepHQ's infrastructure. That works for many people — the cloud model is how most modern health apps work — but it's worth understanding before you sign up. The full feature set also requires a paid subscription, so the free tier has real constraints.
SleepHQ is particularly strong for users who want to share data easily with others. The clean PDF exports and shareable links make it the best option if you're regularly discussing therapy with a clinician.
Summary
Fits people who want an easy interface and simple clinician sharing. Data is cloud-hosted. Some features require a paid subscription.
AirwayLab
AirwayLab is the newest of the three. It runs in your browser — no installation required — but unlike SleepHQ, it processes everything locally. Your SD card data is exported and analysed entirely within your browser tab. Nothing is sent to a server. That's not a marketing claim; it's verifiable because the analysis engine is GPL-3.0 open source.
The free tier is complete, not a preview. You get full AHI breakdown, flow limitation visualisation, RERA identification, leak rate trends, and session history — everything most PAP users need to understand their therapy data. Premium is there for users who want additional features and to support ongoing development; it doesn't gate the core analysis.
AirwayLab's particular focus is on the breathing pattern metrics that matter for therapy understanding — flow limitation waveform analysis, RERA identification, and scoring that experienced CPAP users care about. It's designed for the PAP user who's already read the basics and wants to go deeper.
Summary
Fits privacy-conscious users, and anyone who wants flow limitation and RERA analysis without installing anything. Free tier is full-featured.
Quick comparison
| OSCAR | SleepHQ | AirwayLab | |
|---|---|---|---|
| Platform | Desktop (Win/Mac/Linux) | Web (cloud) | Web (browser-local) |
| Installation required | Yes | No | No |
| Data leaves your device | No | Yes | No |
| Cost | Free | Free / Paid | Free / Paid |
| Open source | Yes (GPL) | No | Engine (GPL-3.0) |
| Flow limitation analysis | Yes (advanced) | Basic | Yes (visualised) |
| RERA identification | Yes | Limited | Yes |
| Clinician sharing | Manual (screenshots) | Built-in | Coming |
| Mobile | No | Yes | Yes |
| Learning curve | Steep | Low | Low–Medium |
When each tool shines
These tools overlap, and each has a place. Many experienced PAP users end up with more than one.
AirwayLab fits when:
- Privacy matters and you don't want data leaving your device
- You want to analyse your data immediately from any computer without installing software
- Flow limitation and RERA patterns are your focus
- You want the analysis engine you rely on to be open source and verifiable
OSCAR fits when:
- You want to inspect raw waveforms breath by breath on a desktop
- You're participating in CPAP forums where OSCAR charts are the shared format
- You're comfortable with a desktop application and want the full waveform view
- You want maximum control over how your data is displayed
SleepHQ fits when:
- You want to share data directly with a clinician
- You prefer a polished, modern interface
- Cloud storage is acceptable for your use case
- You want mobile-friendly access
Many experienced PAP users end up with more than one of these in their toolkit. AirwayLab is built to be the one that does the analysis for you: the same SD card, every night scored automatically, and the data stays on your device.
How AirwayLab fits into your data toolkit
AirwayLab was built specifically for PAP users who wanted a tool that ran in the browser, kept data local, and focused on the metrics that matter for therapy understanding — particularly flow limitation and RERAs, which the device's built-in display ignores entirely.
AirwayLab reads the same SD card files, scores each night for you — flow limitation, RERAs, composite metrics the device never reports — and opens the waveform behind any flag in the browser, with nothing to install on whatever machine you happen to be at. OSCAR has a decade of community development behind it and is a detailed desktop viewer if that is already where you work.
The free-and-always-will-be commitment is real. Core analysis features stay free because every PAP user deserves access to their own data in a readable form. Your data is yours.
Important note on all CPAP analysis tools
OSCAR, SleepHQ, and AirwayLab are all data exploration and visualisation tools. They help you see and understand the information your device records. They do not diagnose sleep disorders, and nothing in any analysis output from these tools should be treated as a clinical recommendation or substitute for professional medical advice. If your data raises questions about your therapy, please discuss them with your prescribing clinician or sleep specialist. These tools are designed to help you have better, more informed conversations — not to replace those conversations.
Frequently asked questions
Is OSCAR still the best free CPAP analysis software?
AirwayLab scores every night automatically in the browser, with no installation required, and still lets you zoom into the waveform behind any flag. OSCAR remains a detailed free desktop viewer with strong community support.
Is SleepHQ free?
SleepHQ has a free tier, but full access requires a paid subscription. Your data is stored on SleepHQ's servers.
Does AirwayLab send my data to a server?
No. AirwayLab processes all analysis in your browser. Your CPAP data never leaves your device. This is verifiable because the analysis engine is open source (GPL-3.0).
Do I still need OSCAR if I use AirwayLab?
Not for the analysis itself. AirwayLab reads the same SD card files, scores each night automatically, charts the trend, and opens the waveform behind any flag in the browser — nothing to install. OSCAR is a dedicated desktop viewer if that is already where you work.
What is the best free CPAP data analysis software for privacy?
Both OSCAR and AirwayLab process data locally with no data upload required. OSCAR is a desktop application; AirwayLab runs in your browser with no installation needed.
Ready to try AirwayLab?
Upload your SD card data now — no installation, no account required, and no data sent to any server. Your browser does all the work.