ResMed H3i vs. H4i Humidifier

I notice on the CPAP.COM site that: "ResMed's HumidAire 4i is engineered to deliver 30% more heated humidification than the H3i. The humidifier is an integrated unit for use with ResMed S8 and S8 II series CPAP machines. The H4i Water Chamber has also increased in capacity up to 390 ml of water." (https://www.cpap.com/productpage/resmed ... -cpap.html)

I find this quite interesting in that the ResMed downloadable User Guides state that the H3i has a capacity of 415ml while the new H4i has a capacity of only 390ml. Hmmmmmm? Gotta' wonder what happened at CPAP.COM

(http://www.resmed.com/us/assets/documen ... er_mul.pdf)

(http://www.resmed.com/us/assets/documen ... er_eng.pdf)

I was able to take a good look at both the H3i and H4i today at a local equipment supplier. The big difference seems to be the heating surface. The heating surface in the H3i water chamber is a fairly small metal disc situated in the centre of the chamber; this metal disc looks to be fairly thick and sturdy, and rests upon a correspondingly-sized heater plate in the humidifier housing. The H4i has a much larger heating surface, of a fairly thin-looking metal which looks much like that used in the humidifiers of the old "tank" series of Respironics machines. This bottom surface of the water chamber sits on a correspondingly-sized heater plate.

Given that the surface area of the H4i is significantly larger than the H3i, I suspect that the water in the H4i would heat up more quickly and perhaps, stay heated more effectively in the event that the ambient room temperature dropped. In theory, I think that this system would make for more effective humidification. This is just my non-physics brain making a guess --the smart people on the forum will, I'm sure, correct me.

So, while the new H4i should provide more humidity, if the technical specs from ResMed are accurate, the H4i tank does not hold more water than the soon to be discontinued H3i.

The other thing that I noticed is that the housing of the H3i humidifier is clear plastic whereas the H4i has a frosted appearance. The Equipment Supplier person and I both commented that seeing the "max. water level" indicator on the H4i is difficult when compared to the H3i.

I've had the pleasure to using both humidifier tanks. I began with the H3i and now am using the H4i. Your theory on the 4i putting out more humidifcation is correct. In fact, I experienced rainout for the first time using the same setting on the 4i as I had always used on the 3i. Room temperature was constant, so that was not a factor in the comparison.

I'm not sure what you mean about the frosting on the 4i tank. My is clear as glass, just like the 3i and the water line is easily discernable.

The biggest advantage I see between the two is that I do not run the 4i dry at night as I often did the 3i and the 4i opens completely for easier cleaning.

Hi
I also have a 4Hi and when I had a cold I ran it at level 9 for 8-9 hrs and it didn't run out. I didn't experience "rainout" either but then it was very warm (for us) that week.
And mine is clear too.

WillSucceed wrote:the H4i has a frosted appearance

mdbarthe wrote:I'm not sure what you mean about the frosting on the 4i tank.

Page 3 should clarify the confusion . . .

http://www.resmed.com/us/documents/h4i_ ... tomers.pdf

WillSucceed wrote:I notice on the CPAP.COM site that: "ResMed's HumidAire 4i is engineered to deliver 30% more heated humidification than the H3i. The humidifier is an integrated unit for use with ResMed S8 and S8 II series CPAP machines. The H4i Water Chamber has also increased in capacity up to 390 ml of water." (https://www.cpap.com/productpage/resmed ... -cpap.html)

I find this quite interesting in that the ResMed downloadable User Guides state that the H3i has a capacity of 415ml while the new H4i has a capacity of only 390ml. Hmmmmmm? Gotta' wonder what happened at CPAP.COM

(http://www.resmed.com/us/assets/documen ... er_mul.pdf)

(http://www.resmed.com/us/assets/documen ... er_eng.pdf)

I can see the numbers WillSucceed quoted in those manuals.
I can also see the follwing, in Jeff's Resmed letter link:

In addition, the H4i offers 30% higher humidity output and 65ml greater water capacity than the H3i, an advantage for patients on very high pressures, particularly those associated with bilevel therapy.

Somebody at ResMed goofed in one of those documents.

jnk's link does indeed clear up some of the confusion.

The "clear" tank is being replaced by the "frosty" tank. In addition, there is a third tank which can be opened, allowing for cleaning inside the tank.

Personally, I like the idea of the sealed tank -one less gasket/seal to leak.

Thanks jnk for posting the link to the "Dear Valued Customer" document.

WillSucceed wrote:jnk's link does indeed clear up some of the confusion.

The "clear" tank is being replaced by the "frosty" tank. In addition, there is a third tank which can be opened, allowing for cleaning inside the tank.

Personally, I like the idea of the sealed tank -one less gasket/seal to leak.

Thanks jnk for posting the link to the "Dear Valued Customer" document.

You are welcome.

There is nothing worse than cloudy confusion--I prefer clear confusion. Thus the "clarification."

jeff

Here's my experience with H3i and H4i.

viewtopic.php?f=1&t=37149&p=323408#p323408

Chalk and cheese

k