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Low Flow Oxygen Concentrator Comparison and Review

Low Flow Oxygen Concentrator Review

Low Flow Oxygen Concentrators are designed to provide continuous oxygen flow of less than 5 liters per minute (LPM). These oxygen machines are designed to accommodate both adults and pediatrics. Since most oxygen patients require only 2 liters of oxygen or less per minute, these low flow concentrators have a very wide application. Some of the low flow oxygen concentrators for sale target the pediatric market since children have a smaller lung capacity. Unfortunately, "low flow" in the mind of many consumers is not an adult oxygen concentrator. However, low flow oxygen concentrators are capable of serving both children and adults and offers many advantages that bigger higher-flow concentrators are unable to provide.

This oxygen concentrator comparison examines the top low-flow home oxygen concentrators on the market, offering 2 to 3 liters of oxygen therapy per minute. These concentrators include two concentrators from AirSep--the VisionAire 2 and the VisionAire 3--and the SimplyFlo from Respironics. A side-by-side comparison of the Low Flow Home Oxygen Concentrators is provided below this review. At the bottom of this page are links to research studies regarding Low-Flow Oxygen Therapy.

Additional oxygen concentrator rankings, reviews and comparison charts can be viewed by clicking on the links below:


Smallest Size Low Flow Oxygen Concentrator

For oxygen delivery systems, smaller is better. Smaller sized oxygen concentrators take up less space and are easier to move from room to room. Weight is another important factor. Pushing a heavy oxygen concentrator down a narrow hallway to another room can be easier with a more lightweight machine. Room-to-room mobility of an oxygen concentrator is significantly increased with a smaller and lightweight concentrator. Since low flow oxygen concentrators have smaller oxygen generators, they are more likely to have a smaller size and lower weight than the 5 liter concentrators or high flow concentrators. The average size for a 5 liter concentrator is 3688 cubic inches and the average weight is 36 pounds. The low-flow concentrators have an average size of 2478 cubic inches and an average weight of 23 pounds. However, it is the small size and lightweight of the Respironics SimplyFlo that brings the average down significantly for this group. The median size is 3372 cubic inches and the median weight is 30 pounds. The SimplyFlo ranks number one for smallest size and lowest weight home oxygen concentrator. The comparison chart below displays size and weight graphically for the three concentrators compared.



Concentrator with the Lowest Power Consumption

Usually the smallest oxygen concentrator provides the lowest power consumption. Such is the case with the low flow concentrators. The SimplyGo concentrator consumes an average of 120 watts while operating. This is the lowest power usage for all home oxygen concentrators. The VisionAire 3 uses 175 watts of power while the VisionAire 2 uses 200 watts of power. The national average for the cost of a kilowatt per hour (KWH) is 0.1256 cents. (Source: Edison Electric Institute, June 2014, Typical Bills and Average Rates Report) The chart below provides the average cost per kilowatt-hour for the continental United States.


Residential U.S. rate map


The chart below displays the average watts per hour for each low-flow oxygen concentrator with the average daily cost and the average annual cost to operate. Also displayed is the average watts and cost for operating a 5 liter concentrator and a 10 liter concentrator as a comparison. Oxygen patients that need 2 to3 liters of oxygen can save from around $134 to $222 annually on their electric bill by purchasing a low-flow concentrator instead of a 5 liter concentrator. These same patients can save between $351 to $439 annually with a low flow concentrator over a 10 liter concentrator. In other words, oxygen patients could buy a new low flow concentrator every 2 to 5-1/2 years from just the savings on their electric bill.

Low-Flow Oxygen Concentrator Power Usage Comparison

5 Liter Average 10 Liter Average SimplyFlo VisionAire 3

VisionAire 2

Average Watts
(Per Hour)
322 519 120 175 200
Daily Watt Usage
(operating 24 hours)
7728 12,456 2,880 4,200 4,800
Average Daily Cost
(0.1256 cents per KWH National Ave)
 $0.97  $1.56  $0.36  $0.53  $0.60
Annual Watt Usage
(24/7 Operation)
2,822,652 4,549,554 1,051,920 1,534,50 1,753,200
Average Annual Cost
(0.1256 cents per KWH National Ave)
$354.53  $571.42  $132.12  $192.68  $220.20




Lowest Noise Concentrator

Noise is measured as sound pressure in decibel units. The OSHA hearing protection guidelines consider decibel levels below 50 as safe and comfortable. Sound levels with decibels between 51 and 84 decibels are considered as non-hazardous. Sound above 85 decibels is harmful.

Noise emissions of oxygen concentrators are generally lower than the sound of human conversation averaging 60 decibels. Oxygen patients do not want to be exposed to more noise than they have to. All three low flow oxygen concentrators in this comparison have a decibel level at or below 50--the safe, comfortable zone. The VisionAire concentrators tie for the 1st place ranking with 40 decibels. The lightweight SimplyFlo generates 50 decibels of noise while operating. See the chart below for the noise level comparison of each low flow concentrator.



Noise Decibel Level Comparison

Noise Level Decibel Chart



Best Performing Low Flow Oxygen Concentrator

Determining which concentrator offers the best performance is measured from four separate factors--continuous oxygen flow, oxygen concentration, outlet pressure and maximum operating altitude. The VisionAire 3 is the best performing low flow oxygen concentrator. It offers 3 liters of continuous oxygen therapy per minute with a maximum outlet pressure of 25 psi. The VisionAire 2 matches the performance of the VisionAire 3 in every aspect except maximum oxygen flow, offering 2 liters instead of 3. The SimplyFlo ranks first for oxygen concentration levels with a slightly higher concentration range of 87 to 96%. All three concentrators can operate up to an altitude of 10,000 feet above sea level.


Model Continuous
(max LPM)
(max psi)
(feet above
sea level)
VisionAire 3 3 87 to 95.5% 25 10,000
VisionAire 2 2 87 to 95.5% 25 10,000
SimplyFlo 2 87 to 96 % 6.4 10,000



Bonus Features

The no maintenance feature of the VisionAire oxygen machines is a nice feature that is significant for many oxygen therapy patients. The VisionAire models come with a back-lined flowmeter to view oxygen delivery. They also come with oxygen flow locking and overdraw protection. An optional oxygen sensor is available for the VisionAire 3 and is standard on the VisionAire 2 concentrator. The VisionAire 2 can be dialled down to a flow setting as low as 1/8 liter per minute for pediatric applications.

Best Low-Flow Oxygen Concentrator

The overall best home oxygen concentrator with low-flow oxygen delivery is the AirSep VisionAire 3. The VisionAire 3 ranks number one for a maximum oxygen flow of 3 liters, number one for the highest outlet pressure (tied with VisionAire 2 at 25 psi) and number one for the lowest noise level (tied with visionAire 2 at 40 decibels). The VisionAire 3, like all VisionAire concentrators, come with a standard 3 year warranty. The SimplyFlo concentrator is just slightly behind the VisionAire concentrators. The Respironics SimplyFlo ranks first for oxygen concentration level, smallest size, most lightweight, and lowest power consumption. Its standard 2 year warranty can be upgraded to 3 years for an additional fee at the time of purchase. If size and weight are a major concern, we would recommend the SimplyFlo over the VisionAire models. If performance is the major concern, the VisionAire 3 is the best choice.

Best Home Oxygen Concentrator Low Flow

Oxygen Concentrator Comparison Chart Low Flow Machines

Invacare Platinum 10 Liter Oxygen Concentrator Nidek Nuvo 8 Liter Oxygen Concentrator Respironics Millennium M10 10 Liter Oxygen Concentrator
Model VisionAire 3 SimplyFlo VisionAire 2
Manufacturer AS096-6 1076773 AS096-8
Model # AirSep Respironics AirSep
Continuous Oxygen Flow
(max LPM)
3 2 2
Oxygen Concentration 87% to 95.5% 87 to 96% 87% to 95.5%
Oxygen Outlet Pressure
(max psig)
25 6.4 25
Operating Altitude
(feet above sea level)
10,000 10,000 10,000
Cubic Size
3372.72 690 3372.72
14.1 10 14.1
20.8 11.5 20.8
11.5 6 11.5
30 9 30
Operating Factors
40 50 40
Average Power Consumption
175 120 200
Made In The USA Yes Yes Yes
Warranty 3 Yrs 2 Yrs 3 Yrs




Low Flow Oxygen Therapy Studies

Burt Cancaster, Author

Vitality Medical
7910 South 3500 East, Suite C
Salt Lake City, UT 84121
(801) 733-4449
[email protected]

Burt Cancaster Profile