Our Criteria

Evidence we accept

We prioritize primary documentation and verifiable sources. When sources conflict, we explain the discrepancy and reduce confidence accordingly.

Manufacturer documents: manuals, spec sheets, drawings, certificates, test reports, warranty terms.
Regulatory / standards evidence: verified listings, conformity documents, pressure-vessel compliance documentation where applicable.
Independent signals: credible clinic feedback, service records, parts availability, repeated patterns in user reports.
What we don’t treat as proof: marketing claims without documents, single anonymous testimonials, or “certified” statements without a traceable record.

What we check (checklist)

This is the core checklist behind every rating. Some items are “gating” (a fail can cap the grade).

1) Safety & risk controls (highest weight)

Fire/oxygen safety approach (materials, ignition risk controls, operational guidance)
Emergency procedures and clearly documented limits
Patient monitoring considerations and safe operating envelope

2) Compliance, certifications & traceability

Documented compliance claims (traceable certificates / standards references)
Clarity on what is certified (model/version) and what the scope is
Pressure-vessel / structural verification evidence (as applicable)

3) Engineering & build quality

Materials, seals, windows, doors, valves, and long-term durability signals
Design maturity: revisions, known failure modes, and how they’re addressed
Maintainability: service access, parts, and downtime expectations

4) Performance & usability

Pressure capability and stability; realistic use-cases (home vs clinical)
Comfort and ergonomics (space, noise, visibility, ingress/egress)
Controls, user guidance, and training requirements

5) Support, warranty & total cost

Warranty scope and exclusions; service network availability
Spare parts lead times; maintenance schedule and consumables
Total cost of ownership (purchase + maintenance + downtime risk)

6) Transparency & documentation quality

Clarity and completeness of manuals/specs
Consistency of claims across documents and pages
Disclosed limitations and known constraints

How we grade (A+ to F)

A+: Exceptional safety profile and documentation, strong verified compliance, proven track record, excellent support. Few/no unresolved red flags.

A / A-: Strong overall. Minor gaps or trade-offs, but no major unresolved safety/compliance risks.

B: Generally solid but with meaningful compromises (support, documentation, design maturity, or limited evidence). Suitable for certain contexts with due diligence.

C: Mixed. Notable limitations, weak evidence, or repeated concerns. Buyers should validate carefully; grade reflects higher uncertainty/risk.

D: Significant issues or lack of verifiable documentation. Only consider with strong mitigation and independent verification.

F: Major safety/compliance red flags, misleading claims, or patterns that suggest unacceptable risk.

Red flags (can cap a grade)

Unverifiable certification claims or missing/contradictory documentation.
Safety-critical omissions in manuals (limits, emergency procedures, warnings).
Patterns of failures without clear corrective actions or support response.
Ambiguous specs (pressure, oxygen delivery, materials) that change across sources.
Service/parts issues that materially increase downtime risk for clinics.

Notes & disclaimers

We are not a medical provider. This site is educational and comparative.
Grades may change as new evidence appears (new revisions, recalls, updated certificates, service changes).
For refurbished/used chambers, condition and maintenance history can dominate the outcome; we typically grade the category more conservatively.

How to read our grades