Frequently Asked Questions

What’s the cost of oxygen generated by an HVO system?

For requirements up to 200 SLPM (standard liters per minute), HVO systems are less costly per unit volume than delivered oxygen in nearly every scenario. To make a proper comparison to delivered oxygen, you must know the price your local gas suppliers charge (which varies widely) and the cost of electricity (generally $0.06 – $0.12 per kWh in the USA).

Assuming a power cost of $0.0673 per kWh, annual maintenance cost of 2%, and 8 daily hours of charging*, HVO systems produce oxygen at a cost of 3 to 4 cents per pound / 7 to 9 cents per kg, depending on configuration. This calculation includes the cost of the system itself. An HVO customer advocate will be happy to create a return-on-investment (ROI) model taking your requirements into account.

*When properly sized, the HVO system will be idle for a time after reaching maximum pressure. As a result, compressors and concentrators typically run for less than a full day, and potentially much less, depending on usage.

Is financing available?

Yes, and we recommend the following lending company:

Which oxygen concentrators do you sell?

HVO sells our own HVO Pro Gen 10 oxygen concentrator, which generates 10 LPM. We also sell concentrators from AirSep and Respironics. See the Expansion and Store pages for more information about those products.

Can I use my own oxygen concentrator(s)?

If your oxygen concentrators all generate the same pressure and flow, you may use them attached to an HVO system. Be aware that concentrators with different output pressures that are joined together on the same manifold will cause the weaker concentrator’s flow to be suppressed. Speak to an HVO customer advocate to learn more about the compatibility of your particular concentrators.

Are the parts in the HVO system oxygen-rated?

Yes. For safety and longevity, we use only oxygen-rated, oil-free parts.

How much oxygen fits in a tank?

HVO systems generate oxygen on demand, but you’ll still need an oxygen storage tank for pressurization and during periods of high usage. How much storage depends on your specific requirements. We sell 6, 20, 30, 60, and 80-gallon tanks, and storage may be extended by interconnecting tanks.

The following table shows the gas volume for all tank sizes at 100 PSI / 6.9 bar (maximum pressure for the Standard compressor) and 150 PSI / 10.3 bar (maximum pressure for the Mighty Mite and MAX compressors):

Tank Size (gallons)Pressure (PSIG)O2 LitersO2 Ft3


Is there a warranty?

HVO systems come with a one year warranty that includes parts and labor. Respironics Everflo and M10 concentrators purchased from HVO are covered either by a one year or a three year warranty, depending on which option you chose at purchase time. All other concentrators that we sell are covered by a one year warranty.

What are the power requirements?

A 15 amp circuit is required for the Main, 15 amps for each Drone, and a separate dedicated circuit is required for each relay box. The relay boxes, which power the oxygen concentrators, have the following amperage requirements:

  • 3-outlet relay box requires 20 amps
  • 5-outlet relay box requires 30 amps

A power surge protector is recommended for the Main.

What’s the electricity cost to run an HVO system?

Every major component of the HVO system requires approximately 590 watts. For example, if you have one Main and three concentrators, that’s 4 major components. 590 x 4 = 2,360 watts. Divide total watts by 1,000 to get kilowatts, which, in this example, would be 2.36 kW. 

Now consider how many hours of the day your system will be charging — not just turned on, but with compressors and concentrators running. Let’s assume that your system charges an average of 8 hours per day.

Lastly, find your local kWh power rate. Say it’s 8 cents per kWh. Your cost (in this example) would be 2.26 x 8 x 0.08 = $1.51 per day.


How long do the compressors last?

Like all machines with moving parts, compressors need to be serviced from time to time. Wear is inevitable as compression causes friction and heat. Our high-powered, two-stage compressors (Mighty Mite and MAX) may need to be serviced every three to four years, depending on usage. Our single-piston compressor (the Standard), needs less frequent service, as much as every four to five years. Results vary depending on specific usage patterns and environmental conditions.

If a compressor does fail, replacing it is fast and easy. Purchase a compressor assembly, and swap the old one out. This repair typically takes less than an hour with common tools and basic mechanical skills.

HVO has a compressor exchange program in which you can send back your old assembly for a rebate that is retroactively applied to the cost of a new compressor assembly. Note that the value of the rebate is dependent on the condition of the returned assembly. We also sell refurbished compressors when they are available.

What operating conditions does the HVO system require?

The HVO system operates best when the temperature is between 55 F / 12.8 C and 90 F / 32.2 C, and the humidity is less than 50%. Plan to have good air-flow in the space where your system is located, using fans and/or AC.

How do I connect my Pro Series system to the Internet?

You can use an Ethernet cable or wifi. If you choose an Ethernet cable, just snake the cable up under the headbox and plug it in to the Ethernet jack located on the IoT computer. If you need help, the manual below has a brief section that describes how to connect an Ethernet cable. Mainly, though, this manual talks you through the process of setting up wifi.

NOTE: For systems purchased prior to June, 2020, you should contact us for assistance with wifi configuration.

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I have more questions!

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