Does ResMed H5i tank ever feel warm?

[Iowamv]

Not sure my humidifier is working as it should. I empty the tank every day and let it air dry. I notice that when I remove it immediately after turning the machine off in the morning neither the water in the tank nor the warming plate underneath it are warm to the touch. I'd say they feel room temperature. Definitely not cold, but for some reason I thought at least the warming plate would feel warm/hot to the touch. I've got it turned up to 84 (what can I say, I like warm air).

Is this normal?

[Julie]

Is it giving you warm air when you fall asleep? Go by that, not what it feels like when you're up. If you're not getting the temperature you want when you're sleeping, then something should be checked, but if you're happy with what you get, don't worry about how it feels when you're up.

[Iowamv]

It isn't cold air, but it doesn't seem warm. On a couple of occasions I've thought the air seemed really warm, but on most nights I'd describe it as room temperature or luke warm. 84 degrees is lower than body temperature, so maybe that is normal.

I'm really just curious to hear whether anyone else has taken one out right away in the morning and felt heat (as opposed to absence of cold)...

[KarenK]

I too have the same question. I started with a F&P Icon, and that water was WARM. I don't sense really warm water in my nose, and I agree that the water is not warm. Neither is the hose.

[OKCSleepDoc]

Relative Humiidity (RH) is the amount of water vapor in the air as a percentage of the maximum amount it can hold (saturation point, 100%) at a specific temperature. Absolute humidity (AH) is the total amount of water vapor (mg/L) in the air and is independent of temperature. The relationship between RH, temperature and AH is shown in Figure 1. For a RH of 90%, if the ambient air temperature is 55°F (13°C) the AH is 10 mg/L but at 90°F (32°C) the AH is 30 mg/L with RH still 90%. To maintain a consistent level of humidification during therapy the AH, not the RH, needs to be constant.

Image is in this reference article: http://www.resmed.com/us/assets/documen ... -paper.pdf

Climate Control is a control algorithm that automatically adjusts the humidity delivered by the S9 system in response to ambient conditions of temperature and humidity. It also
adjusts for changes in pressure and flow rate. This is to maintain a target AH at the mask equivalent to a RH of 80% at the user set temperature.

So I could be wrong but....The way I think of climate control with Resmed H5i is this. I imagine that I am in the Amazon. If it were 85 degrees, or if it is 100degrees there is a certain level of humidity that is possible at that temperature. The resmed H5i targets 80% of that amount and then measuring the ambient humidity in your room, determines if it needs to heat the plate or not to deliver the amount of humidity you are asking for. So essentially, if you like it warm (perhaps your room temperature is also warm?) the machine may not need to warm up the water as much to deliver the humidity you are asking for. It is not going to warm up the water to 84 degrees, it is only targeting the humidity you are asking for.

Does that make sense?

[KarenK]

Yes, BUT why then is the F&P water warm when I change it or add to it, while the ResMed is room temp or less? Because of a different algorithm?? And if the hose is "heated" why don't I feel that either? Just wondering.

[Bobshouse]

I was wondering the same thing. I turned mine up one time to the max and it did start heating the plate. I turned it back down as I just wanted to see if it worked.

[Denial Dave]

I keep my humidity setting at 5..... the bottom of the tank rarely feels much warmer than room temp..... but the heating plate inside of the humidifier will get warmer.


I think the internal max temp of the unit itself is 160... Once it gets to 160 degrees, it cycles at that temp until you turn it off.

[SleepWellCPAP]

Though OKCSleepDoc's post is very thorough and scientifically addresses the issue in question, my response has always been very similar to Julie's.

Regardless of the perception of heat on the heater plate, or water usage by the way, always go by how you feel not what you think is logical. If you are neither dried out or stuffed up, it's working. Make adjustments or consider functionality only if you have upper airway issues.

I have checked with tech support in the past regarding perceived heat and water consumption and have always been given the same response, you will rarely feel heat on the plate and unless you have symptoms, neither is relevant.

I do like the pdf link OKCSleepDoc posted for sure though. Will have to review that more closely later. Thanks for posting that!

[billbolton]

Definitely not cold, but for some reason I thought at least the warming plate would feel warm/hot to the touch.

The role of the humidifier is to humidify, not to heat anything per se. Unless you are running a high humidity level in a cold ambient environment, there's simply no need for a lot of heat to achieve humidification

For most users, the only time the H5i warming plate/tank will ever be noticeably "warm" is if you have used the "warming up" function, as that ramps up the warming plate temperature to get the humidification to the selected level, then backs it off to whatever (usually low) temperature is needed to maintain the humidification level.

Cheers,

Bill

[Sir NoddinOff]

The short answer is that if you like warm wet air from your CPAP, both the PR and ResMed climate control algorithms are going to fall short for you. I've had both machines and have some experience in the matter.

A while ago I got a after-market heated Hybernite hose that just plugged into any AC outlet... that sucker heated up nicely and helped get the temps and humidity up somewhat, however condensation occurred when the local weather cooled down in the winter. There's nothing like a dripping mask to wake you up in the middle of the night. Anyway, it's kind of a fine balance where it all works and meets your preferences - you'll just have to find that point for yourself since everybody is different.

[Uncle_Bob]

The short answer is that if you like warm wet air from your CPAP, both the PR and ResMed climate control algorithms are going to fall short for you. I've had both machines and have some experience in the matter.

The algorithms prioritize rainout control over heat/humidity output.
If anyones likes it hot and humid i have a standalone humidifier i can recommend.

https://www.cpap.com/productpage/fisher ... ifier.html

The pictures for this product also include some useful information on humidification for CPAP in general.

~UB

[torontoCPAPguy]

The H5i humidifies by blowing the dry room air over the water. Turning up the temperature of the humidifier will both heat the air and the water so that more moisture is in the air as it passes over the water in the tank, which SHOULD feel somewhat warm but not hot. Unfortunately, the nicely warmed and humidified air will tend to cool off on its travels to your face through the tubing; so when I am inclined to humidify or heat the air being presented (a in the winter time here in Toronto), I use my heated hose(s) to ensure that I get warm air at my face. This will also help to maintain the humidity in the air flow and prevent "rain out" where the humid air loses its humidity in the tubing, where it either collects or runs into your mask if you don't 'engineer' a low point in the tubing. Best bet is heated hosing. Hope this sheds some light on the S9 system anyway.