OSCAR vs SleepHQ vs SomniCharts: Which Tool Reads Which Machine

If you own a CPAP machine and want to actually read the data it records every night, your first question isn't "which tool has the prettiest charts" — it's "which tool can even open my machine's files." Device support is the make-or-break feature, and it varies more than most people expect across the three most popular options: OSCAR, SleepHQ, and SomniCharts. This guide lays out a factual support matrix so you can match the tool to the machine on your nightstand.

This is part of our CPAP Data Tools & Apps hub, where we compare the software that turns a raw SD card into something you can understand.

Why machine support matters most

Every CPAP brand writes its therapy data in its own proprietary file format. ResMed uses a folder structure with EDF files; Philips DreamStation 1 uses a different layout; Löwenstein (Weinmann) prisma machines use yet another; and Fisher & Paykel's SleepStyle stores data on a small InfoUSB stick. A tool can only show you your AHI, leak rate, and pressure if its developers have written a parser for your machine's exact format.

That's why a feature list ("flow rate waveform!", "leak detection!") is almost meaningless until you confirm the tool reads your device. A beautifully designed analyzer that doesn't support your brand is worth nothing to you, while a plainer tool that opens your card every time is invaluable.

Two practical notes before the matrix:

• Single-night numbers are noise. Whatever tool you choose, the value comes from watching trends over weeks, not obsessing over one bad night. Look for software that makes reading your CPAP data over time easy.
• Leak data is the trust anchor. A large unintentional leak can invalidate or under-report your AHI, because the machine can't reliably score events when air is escaping. Make sure your tool surfaces leak clearly — see CPAP leak rate: what's acceptable.

OSCAR's supported machines

OSCAR (Open Source CPAP Analysis Reporter) is the free, open-source desktop successor to the discontinued SleepyHead. It's the gold standard for hobbyist analysis and the deepest free tool available. It runs on Windows, macOS, and Linux — but not on Chromebooks or in a browser, and it has no automatic event re-scoring (you read the charts yourself).

OSCAR's verified device support:

• ResMed — excellent. S9, AirSense 10, AirSense 11, and AirCurve bilevel/ASV models are all well supported.
• Philips Respironics DreamStation 1 (and System One) — supported.
• Fisher & Paykel SleepStyle — supported, with some caveats around the InfoUSB workflow.
• Löwenstein prisma SMART — limited support.

OSCAR is a phenomenal tool if you're comfortable installing desktop software, importing your card manually, and interpreting raw charts. If that learning curve appeals to you, our OSCAR CPAP software guide and how to read OSCAR charts in plain English will get you started.

The DreamStation 2 encryption gap

Here's the single most important compatibility fact in this entire comparison: OSCAR cannot read the Philips DreamStation 2 (DS2). Philips encrypted the SD-card data on the DS2, and that encryption has not been opened up to OSCAR or other community desktop tools. So if Philips sent you a DreamStation 2 as a recall replacement — millions of patients received one — your familiar OSCAR workflow simply stops working.

This catches a lot of people off guard. They used OSCAR happily with a DreamStation 1, received a DS2, popped in the card, and found nothing readable. The data is there on the card; it's just locked. We cover the why and your options in depth in Philips DreamStation 2: why its data is encrypted. (For background on the recall itself: an FDA inspection report and independent lab tests commissioned by Philips raised concerns about volatile organic compounds, including formaldehyde, from the original foam — the FDA requested additional testing and advised continued device use while testing was pending. We keep that story neutral in our Philips recall explainer.)

SleepHQ's supported machines

SleepHQ is a cloud-based service: you upload your SD-card data through a browser (or its uploader), and it renders OSCAR-style charts online. It has a free tier and a paid Pro tier, and it leans toward the ResMed community, though its device list is genuinely broad.

SleepHQ's verified device support:

• ResMed — S9, AirSense 10, AirSense 11, and AirCurve. Strong support.
• Philips DreamStation 1 and DreamStation 2 — yes, SleepHQ reads the encrypted DS2.
• Fisher & Paykel SleepStyle — supported.
• Löwenstein prisma / SMART — supported.

SleepHQ is the most device-comprehensive of the three on paper, and its DS2 and Fisher & Paykel coverage are real advantages. The trade-offs are that it remains ResMed-leaning in its feature depth, gates some functionality behind a paid Pro subscription, and still presents data in an OSCAR-style format that assumes you'll do the interpreting. We compare the cloud experiences head-to-head in SomniCharts vs SleepHQ.

SomniCharts' supported machines

SomniCharts is a cloud-based analyzer with a different emphasis: it imports your data and explains it in plain language automatically, rather than handing you raw charts to decode. You upload through any browser — no desktop install — and SomniDoc, its built-in analysis layer, walks you through what your numbers mean.

SomniCharts' verified device support:

• ResMed — S9, AirSense 10, AirSense 11, and AirCurve bilevel/ASV.
• Philips Respironics, including the DreamStation 2 — SomniCharts reads the encrypted DS2 data.
• Löwenstein prisma — supported, including the under-served prisma line that most tools handle only partially.

One honest limitation: SomniCharts does not currently import Fisher & Paykel SleepStyle data. If you're on a SleepStyle, OSCAR or SleepHQ are your paths today (see Fisher & Paykel SleepStyle: InfoUSB data and OSCAR caveats).

Where SomniCharts shines is the awkward middle of the market. If you have a DreamStation 2 or a Löwenstein prisma, your options narrow fast — OSCAR can't open the DS2 at all and only partially handles prisma, and many "ResMed-first" tools treat Löwenstein as an afterthought. SomniCharts reads both of those machines, plus ResMed, and adds plain-language interpretation of your AHI, leak, pressure, and event types on top. The Löwenstein experience in particular is detailed in our Löwenstein prisma data guide.

Side-by-side support table

Here's the verified matrix. "Limited" means partial support that may not cover every model or metric; "No" means the tool cannot read that machine at all.

A few takeaways from the table:

1. For Fisher & Paykel SleepStyle owners, OSCAR or SleepHQ are the answer — SomniCharts doesn't import it yet.
2. For DreamStation 2 owners, OSCAR is off the table; choose SleepHQ or SomniCharts.
3. For Löwenstein prisma owners, SleepHQ and SomniCharts give you the fullest reading; OSCAR is limited.
4. For ResMed owners, you're spoiled for choice — all three read your machine well, so pick based on whether you want a free desktop tool, an OSCAR-style cloud view, or automatic plain-language analysis.

Whichever you choose, remember the point of the data isn't to self-manage your therapy — it's to spot trends and bring informed questions to your clinician. If your residual AHI creeps up, your leaks spike, or central events start appearing, that's a conversation to have with your provider rather than a setting to chase on your own. Our guides on what is a good AHI on CPAP and central apneas showing up on CPAP explain what those patterns mean before you walk into that appointment.

Frequently asked questions

Can OSCAR read a DreamStation 2? No. The DreamStation 2 stores its SD-card data in an encrypted format that OSCAR (and other community desktop tools) cannot decode. SleepHQ and SomniCharts can read DS2 data.

Which tool reads the most machines? SleepHQ has the broadest verified list (ResMed, both DreamStations, Löwenstein, and Fisher & Paykel). SomniCharts covers ResMed, Philips including the DS2, and Löwenstein prisma but not Fisher & Paykel. OSCAR covers ResMed, DreamStation 1, Fisher & Paykel, and prisma (limited) — but not the DS2.

Is OSCAR still the best free option? For desktop users who want depth and don't mind reading raw charts, yes — OSCAR remains the deepest free tool. It just won't open a DreamStation 2 and doesn't run on Chromebooks or in a browser.

I have a Löwenstein prisma — what should I use? SleepHQ or SomniCharts give you the fullest reading. OSCAR's prisma support is limited. SomniCharts additionally explains the prisma data in plain language; see the Löwenstein prisma data guide.

Do any of these let me change my CPAP pressure? No — and you shouldn't change prescribed pressure on your own. These tools help you understand your data so you can have an informed conversation with your sleep clinician. See can I adjust my own CPAP pressure? for what the data can and can't tell you.