How can I check if my ClimateAir actually heats up?

[NoddingHacker]

I have a feeling my resmed 10 ClimateAir doesn't actually heat up, but I want to be sure. How do I check it? I have a Termapen One which is very accurate. But how do I measure the temperature of a tube? I thought about placing a wet paper towel on the tube, let it run for 10minutes, and then place the thermometer probe into the wet towel.

[Jay51]

I have an s9 adapt asv with a climateline heated hose.  One way to tell would be to try it at it's highest heat setting and then try it at it's lowest heat setting and see if there is a difference.  At highest heat level, I sure can tell it's working.