1. Establish what the flow figure means
Before comparing any two machines, confirm whether each quoted mL/min refers to separated hydrogen or to a hydrogen-oxygen mixture. Roughly a third of a mixed-gas figure is oxygen by volume, so the comparison collapses without this answer.
PEM/SPE cells make separation possible; alkaline and “HHO” designs generally do not separate at all.
2. Ask who verified the purity
A purity percentage is only as good as its provenance. Look for a named laboratory, a report reference and a described method. Our inhalation systems are covered by third-party QTT reports LH2025050017 and LH2025050018.
Certification marks — CE, FCC, RoHS — belong in the same category: real, checkable, and about the hardware rather than any medical status.
3. Match output class to your session pattern
One user with a single daily session is well served by a lower-output unit. Two or more users, longer sessions, or a practitioner setting where the machine runs most of the day, push you toward higher-output platforms with the thermal headroom to sustain it.
Check the stated duty cycle explicitly. A unit rated for an hour at a time will not enjoy being run for six.
4. Consider the room, not the spec sheet
Noise and footprint decide whether a machine gets used. If the session will happen next to you while you work or read, fan noise matters more than a hundred millilitres of extra output.
Portability is worth paying for only if you will genuinely move it — the Go class exists for people who travel or move between rooms.
5. Price the ownership, not the purchase
Distilled water, replacement cannulas, filters and eventual stack service are the ongoing costs. They are modest, but they are the difference between a machine that stays healthy and one that quietly degrades.
Warranty terms and parts availability tell you what the manufacturer expects the service life to be, which is more informative than any marketing figure.