Editorial policy
Trace the number or do not publish it.
CPAP power guidance sits next to medical equipment and electrical safety, and a wrong number here isn't a harmless typo — it's a battery that dies four hours into the night. So the standard on this site is deliberately stricter than a typical affiliate roundup: every figure needs a source that can be named, and every estimate needs assumptions that can be checked. This page explains what that means in practice.
Where the numbers come from
Device manuals, manufacturer compatibility tables, and regulatory documentation come first — they are the only sources allowed to establish a core spec like battery capacity, machine draw, or airline approval status. When a manufacturer document doesn't answer the question, the next tier is a named technical source with a reproducible method, cited so you can read it yourself. Retail listings sit at the bottom: they're used only for availability and configuration details, and only when those details are verified separately. Community forums can point out something worth investigating, but a forum post never establishes a spec or a compatibility claim on this site.
How runtime estimates work
Every runtime estimate exposes its inputs: battery capacity, machine load, conversion losses, reserve margin, and accessory assumptions like the humidifier and heated hose. Real-world load varies with pressure settings and humidity, so a range is preferred over a single confident-sounding number — a universal "this battery lasts two nights" claim is exactly the kind of false precision this site was built to avoid. When something is uncertain, the estimate says so instead of hiding it.
What "tested" means here
Words like "tested" and "measured" are reserved for cases where the site has retained actual evidence of the test setup and its result. Everything else is labeled as what it is: analysis built from published documentation. This distinction is easy to blur and most sites blur it — a spec sheet gets rewritten in first person and suddenly reads like a lab report. That doesn't happen here. If a figure is manufacturer-stated, the guide says so.
Commercial independence
The site earns commissions through affiliate links, disclosed on every page that carries them and explained in the affiliate disclosure. That compensation does not change the evidence standard or the ranking method. A product can be excluded — and products have been — for poor compatibility, unclear specifications, weak support, or documentation that couldn't be verified, regardless of what it would have paid. There are no sponsored rankings and no paid placements.
Corrections
When an error is found — by a reader, by a re-check of sources, or by an internal audit — it gets corrected in the page where it appeared, and the affected estimates get updated with it. Sources change too: manufacturers revise specs, products get discontinued, airline rules shift. Guides are re-checked against their sources rather than left to drift.
The line this site doesn't cross
Nothing here is medical advice. The site covers the electrical and product-selection side of backup power — how long a battery lasts, what fits what, what the rules allow on a plane. Whether and how you use your therapy device is between you, your equipment manufacturer, and your care team.