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How to choose the right HVO model

HVO gives you a choice between a basic, reliable product, dubbed the Classic™️, and one that is “cloud-connected”, with sophisticated data tracking, monitoring, and configuration options, which we call the Pro Series™️. In this post, you’ll learn the differences between them, and how to decide which is best for your application.


A no-frills oxygen-generating system that is safe, reliable, affordable, and easy to service. It supports pressure setpoints of 30-100 PSI and 100-150 PSI. It comes with an oxygen concentrator warm-up feature that enables you to delay the storage of generated oxygen until high purity is attained. Choose a delay of 0, 30, 60 or 90 seconds.

Pro Series™️

The Pro Series™️ extends the capabilities of the Classic™️ by adding “Internet of Things” (IoT) features that enable the status of your HVO system to be tracked and monitored in real-time. We call our IoT solution “Seeing Eye™️”, a nod to the service dogs that help lead the sight-impaired.

The Pro Series™️ contains sensors that monitor the critical metrics of your HVO system, including tank pressure, oxygen purity, barometric pressure, system temperature and humidity. An optional Mass Flow Sensor may be purchased to measure the outbound flow of oxygen in liters per minute (LPM).

Get Your IoT Here

The Seeing Eye™️ web portal allows you to view a graph of recorded metrics. A cloud monitoring service notifies interested parties via text and/or email about system issues such as high system temperature or low oxygen purity.

In addition, the Pro Series headbox is equipped with an LCD that displays the current sensor readings, such as tank pressure and oxygen purity.

Lastly, the Pro Series is able to receive software updates from the cloud so that the system’s behavior can be modified remotely. For example, it’s possible to change the high and low pressure setpoints or the concentrator warm-up delay with a software update.


For both the Classic™️ and the Pro Series™️, you may choose one of the following compressors:

  • Standard: Achieves a tank pressure of 100 PSI with oxygen input of up to 45 LPM. Requires a minimum input flow of 10 LPM.
  •  Mighty Mite: Achieves a tank pressure of 150 PSI with oxygen input of up to 45 LPM. Requires a minimum oxygen input flow of 20 LPM / two 10 LPM oxygen concentrators.
  •  MAX: Achieves a tank pressure of 150 PSI. Accepts as much as 55 LPM of input and requires a minimum of 30 LPM / four 10 LPM oxygen concentrators.

The input flow is the sum of the gas produced by the oxygen concentrators connected to the HVO system.  Oxygen concentrators typically produce 5, 8 or 10 LPM each. We recommend purchasing 10 LPM concentrators, all of the same type. Specifically, we advise against mixing concentrator types (brands, models, output ratings) in a single system, as variations in pressure can reduce efficiency.

Oxygen Storage Tanks

HVO oxygen storage tanks come in 20, 30, 60, and 80-gallon sizes. Having lots of stored oxygen is beneficial when oxygen usage spikes. However, if your usage regularly exceeds what the system is generating, you will need more input, i.e. more concentrators, and possibly more compressors (drones).

As a general rule, you should match the number of oxygen concentrators to each tank size as follows:

  • 20-gallon: 1 – 3 oxygen concentrators
  • 30-gallon: 2 – 4 oxygen concentrators
  • 60-gallon: 3 – 5 oxygen concentrators
  • 80-gallon: 4 – 5 oxygen concentrators

Where there is overlap, consider whether growth is likely, i.e. whether you will add more oxygen concentrators in the future. If so, choose the larger tank size.

HVO storage tanks are oxygen-rated, meaning that they are designed and treated to store oxygen safely.

What’s the best combination of options?

Here’s a list of important questions to help you decide which model, compressor, and tank size to choose:

  • What is the required oxygen flow rate? You should know the average flow rate you require in Liters per Minute (LPM). Take that number and add 5, then divide by the LPM output rating of the oxygen concentrators you plan to purchase and round up. Now you know the number of oxygen concentrators you’ll need. 
    For example, for a flow rate of 20 LPM, add 5 to get 25 LPM. Divide by 10 LPM which yields 2.5 rounded up equals 3. You should plan to attach three 10 LPM oxygen concentrators.
  • How consistent is your oxygen usage throughout the day? For inconsistent usage (the typical case) you’ll want a larger or extra storage tank and one or more extra oxygen concentrators to handle peak usage periods. If usage is consistent, you can use the number you calculated above.
  • How likely is it that your overall oxygen usage will grow over time? If it’s very likely, choose a system that has some “headroom”, meaning you can add oxygen concentrators. For example, you may choose a 5-outlet relay box instead of the 3-outlet model. If there’s uncertainty, keep in mind that the HVO system is modular and expandable, so you can start small and add components as your requirements become better known.
  • What is the output pressure requirement? If you are a veterinarian running oxygen cages, you probably need at least 50 PSI. This would eliminate the Standard as an option since the tank pressure with this model will go down to 30 PSI before starting to refill, whereas the restart pressure for the Mighty Mite and MAX is 100 PSI.

Remember that the larger the tank size and the higher the maximum tank pressure, the more stored oxygen will be available to handle peak usage. Find out exactly how much oxygen is stored for the various pressures and tank sizes on the FAQ page.

Here are some scenarios:

Scenario 1: Small
You require 15 LPM of constant oxygen output at a pressure of 30 PSI. Consumption doesn’t vary much throughout the workday. In this case, an HVO Standard 20 gallon system (or HVO 2-Go) with two 10 LPM oxygen concentrators will get the job done.

Scenario 2: Medium
You require 30 LPM of constant oxygen output most of the time, with occasional peak usage of 50 LPM, and an output pressure of 50 PSIG. In this case, a Mighty Mite 60 gallon system with three 10 LPM oxygen concentrators is your best choice. The 50 PSIG pressure requirement is above what the Standard can consistently produce. Store more oxygen for use during peak usage periods by purchasing a larger storage tank.

Scenario 3: Large
You need 50 LPM of constant oxygen output with peak usage of 80 LPM. The MAX will be your best choice here, as you’ll be able to attach six 10 LPM oxygen concentrators. Another way to grow an HVO system is by adding drones and/or storage tanks. For more information, see the post “How to expand your HVO system.”

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