Commercial chambers usually take less time to start each session, especially if you don't want to wait so long for slower start up times. In a clinical setting, when there are several patients waiting to use the chamber, faster start up times and chambers that are easier to clean are always preferred.
Some people have inner ear problems and prefer slower inflation times so buying the best compressor is not necessary. The inflation time should not exceed the speed that a person can equalize their inner ears as the pressure increases. Just like you wouldn't speed to the bottom when scuba diving, they tell you to go very slowly so you don't damage your ears.
Note: Before you get a chamber know the inflation time. Some can take twice as long as another and some have flow rate setting where you can change the speed of air going into the chamber. If someone is putting a kid in it, I would make sure you know the correct flow rate so you don't hurt the ears.
Pressure in the inner ear if the chamber is inflated too fast can cause damage, not just the uncomfortable feeling. If the chamber inflates too fast with the factory compressor, you can always buy a cheaper, slower filling after market compressor. Also some manufacturers have manual relief valves to adjust the fill rate.
Some compressors have pumps that have have dual pumps so they can make the inflation time quicker. Many clinics use this because taking a few extra minutes over the day can mean an extra half hour they can charge someone to use the chamber. It is not fair to leave a someone in their and not know if the inflation pressure speed is too high. If the clinics has like 4 hyperbaric chambers, and they are putting one person in after another, make sure you request the technician to stay there and monitor yourself and especially a kid that doesn't know to ask to turn it down.
But, the good thing about the models with dual pumps is that once they inflate the chamber, they pump more air through the hyperbaric chamber and the air doesn't get as hot as their is more air exchange. Remember that moving air under pressure creates friction, this is how it gets hot. Even if a person is not in the chamber, the air will always start to get warm towards the end of the session.
Some compressors create more friction from the start depending on if its a piston or rotary or the other types of compression technologies. All of them will inflate the hyperbaric chamber but all do it with different speeds and frictions. If the person gets hot easily, you may want one type over another. Each hyperbaric chamber company usually has a different brand of compressor and inflation time. We timed each and each can be off by up to 3 times the speed.
Please see my air compressor page to learn more about the compressor to get a better understanding of the compressor before buying a chamber. See the air compressor page here.
Note: The bigger the chamber the longer it takes to inflate it but this is with the standard compressor that comes with it. I am not trying to imply anything but the compressors that are used with the chambers that have the release valves that let the chamber go to 1.5 ATA have much more powerful compressors. Ask to get one of these types although in the USA they won't sell you the 1.5 ATA release valve but it is legal to buy the compressor. The compressors usually come in a different box so if you don't want the compressor that comes standard with the chamber, most companies will not sell you the chamber without the compressor as its considered a medical device. Having two dual compressors working in sync allows for super fast inflation time and keeps the chamber super cool as it circulates much more oxygen that the chamber usually comes standard with.
Having dual compressors in sync and having the sound dampening cooling hose just makes the whole hyperbaric experience much more comfortable and you probably won't be sweating in the chamber, even in the summer.