A concentrator specification is useful only when it describes the exact model you are considering. Compare it with the written oxygen prescription, not just another machine’s headline capacity. Keep the user manual and supplier’s written answers alongside the brochure.
Start with delivery mode and flow
Continuous flow is normally expressed in litres per minute. A pulse-dose device releases oxygen in response to detected breathing, and its numbered settings are not equivalent to continuous-flow litres per minute. Do not choose a portable setting by matching the number on a stationary machine.
Check the minimum and maximum rated flow, the available setting increments and compatibility with the prescribed cannula or other interface. Where the prescription differs between rest, activity and sleep, the equipment needs to accommodate the relevant requirements.
Read concentration together with flow
Look for the oxygen-concentration range and the flows over which it is claimed. Also find the stated test or operating conditions. “Up to” a particular concentration is less informative than a documented range at the required flow.
For example, 93% ±3% means 90–96%. A reading outside that stated range at rated operation needs assessment; it should not be dismissed merely because the device is near its maximum flow. Nor does choosing a larger unit guarantee better concentration, lower noise or longer life.
Check the conditions in your home
Find the permitted temperature, humidity, altitude, ventilation clearance and duty or duration instructions. Confirm the voltage and frequency requirements. If you are planning travel or use in a different location, check that location too.
Power consumption in watts helps estimate running cost. A value in volt-amperes, or VA, is not interchangeable with watts. Backup-power selection also needs consideration of startup demand and compatibility; ask the supplier and a qualified electrical professional rather than sizing it from one brochure number.
Understand convenience claims
Weight and dimensions matter for moving and positioning the unit. For a noise figure, ask what test conditions were used; differently measured figures are not a reliable direct comparison. Consider whether the controls and alarms are clear to the person who will use them.
Ask what an oxygen indicator actually shows. Some devices provide a warning below a threshold; others display a measurement. Neither is a blood-saturation monitor. Confirm alarm meanings, startup behaviour and the required response from the manual.
Include support in the comparison
Confirm included accessories, cleaning tasks, service arrangements, warranty coverage and any consumable costs. Ask for applicable regulatory and certification documents identifying the relevant product and the scope of each claim. A logo on a brochure is not a complete explanation of what was assessed.