Written and maintained by CASRAI Editorial Board
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General product information from published instructions, not medical advice. Whether a person uses humidification, and at what oxygen flow rate, is decided by their prescriber.
Short answer
An oxygen concentrator humidifier is a water bottle placed in the oxygen line between the concentrator’s outlet and the nasal cannula. It is an optional accessory in at least one major manufacturer’s setup instructions, and the water, cleaning and replacement guidance comes from the bottle maker and the supplier rather than from the concentrator manual alone.
Definition and scope
A humidifier bottle (also called an oxygen humidifier bottle) holds water that the oxygen passes through on its way to the cannula. It is a separate component from the concentrator. In the Respironics EverFlo / EverFlo Q user manual, the parts list names the “Humidifier Bottle”, a “Mounting Strap” and a “Humidifier Connector Tube”; the accessories list includes the connector tube alongside the air inlet filter. The concentrator makes the oxygen, and the bottle is an add-on to the outlet line. For the concentrator itself, see what an oxygen concentrator is.
How it connects in practice
The EverFlo / EverFlo Q manual (Respironics, 2008) describes two configurations. Without a humidifier, the nasal cannula connects directly to the oxygen outlet port. With one, the chain is: oxygen outlet port, humidifier connector tube, the top of the bottle, then the cannula. The bottle sits on top of the device, held by the mounting strap, and the connector tube is kept behind the filter door.
The detail worth noticing is that the concentrator manual hands the bottle’s filling and the final cannula connection to the humidifier bottle maker’s instructions. See oxygen tubing and what a nasal cannula is for the parts on either side of the bottle.
Who gives the instructions: what each source says
Instructions are split between three parties: the concentrator manufacturer, the humidifier manufacturer and the home care or medical supply company. The table shows how two published sources divide the topic.
| Question | EverFlo / EverFlo Q manual (Respironics) | American Lung Association, Using Oxygen at Home |
|---|---|---|
| Is a humidifier required? | Setup offers a path “if you are not using a humidifier” and a path “if you are using a humidifier”. | Refers to a humidifier bottle “if you have” one. |
| Who sets the filling instructions? | The humidifier manufacturer’s instructions. | Addresses users directly in its own publication. |
| Who sets the cleaning instructions? | The home care provider or the manufacturer, when a humidifier is used. | Addresses users directly in its own publication. |
| Who sets the replacement interval? | Not stated. | Refers the user to the medical supply company. |
| Output and flow | Concentration is rated at 90-96% from 0.5 to 5 LPM on most models (87-96% on models 1020007 and 1020008). | The flow rate comes from the healthcare provider. |
Where it matters for labs, clinics and supply decisions
- Parts belong to different makers. The mounting strap and connector tube are listed as parts of the EverFlo concentrator, while the bottle’s filling and connection details belong to the bottle’s manufacturer. A bottle is therefore not interchangeable by assumption; the instructions for the specific bottle govern the cannula connection.
- The replacement interval is a supplier or manufacturer statement. The American Lung Association refers users to the medical supply company on this point, so it is not a universal figure.
- Operating conditions affect output. The EverFlo manual warns that operating outside the specified voltage, flow, temperature, humidity or altitude “may decrease oxygen concentration levels”.
Common misunderstandings
A humidifier bottle is not part of how the concentrator makes oxygen
It sits after the outlet port. The concentration ratings in the manual describe the device’s output, and the bottle is an accessory in the delivery line.
Heated humidification is a different question
The oxygen tubing insert covered in our oxygen tubing guide cautions against use with heated humidification because moisture can accumulate, and the same guide links water in the tubing to an overfilled humidifier. A bottle-type humidifier and a heated system should not be treated as the same thing.
The flow setting is not a humidifier setting
The American Lung Association states that the flow rate comes from the healthcare provider. The bottle does not change that. For how flow rate relates to cannula choice, see the nasal cannula flow rate guide.
FAQ
What is an oxygen concentrator humidifier?
A water bottle connected between the concentrator’s oxygen outlet and the cannula, supplied through a connector tube. In the EverFlo setup it mounts on top of the device with a strap.
What is an oxygen humidifier bottle?
The same component: the bottle that holds the water. Its filling and cannula-connection instructions come from the bottle’s manufacturer, as the EverFlo manual notes.
Do you have to use one?
The EverFlo / EverFlo Q manual provides setup for use with and without a humidifier. Whether a particular person uses one is a decision for their prescriber.
Who decides how often the bottle is replaced?
The medical supply company or the bottle’s manufacturer; the American Lung Association refers users to the supplier.
Sources
- Respironics, EverFlo / EverFlo Q User Manual (2008), as hosted by Air Liquide Healthcare Ireland: https://ie.healthcare.airliquide.com/sites/alh_ie/files/2024-02/everflo-user-manual.pdf. Date checked: 2026-10-30.
- American Lung Association, Using Oxygen at Home (OX4, 2020): https://lung.org/getmedia/a3d0c90d-9b94-4318-9e4f-8d3abfcfbc26/OX4-Using_Oxygen_at_Home-2020-v2. Date checked: 2026-10-30.
