Tube amp heat questions...

Hi all, I recently joined the ranks of tube amp owners by adding an ARC VSi55 to my setup. Love it, and it doesn't seem to put out a ton of heat, but it's getting cooler here in Phoenix so I may feel differently next July.

I did search thoroughly through past threads to see if these questions were asked, and found some good threads about summer amps vs. winter amps, but not my specific questions:

- Is there a direct correlation between tube amp wattage per channel and heat generated, such that for example any 100wpc tube amp will always put out more heat than a 25wpc tube amp?

- If that is the case, it is because higher WPC = either more tubes and/or larger tubes?

- If that is not the case, is heat a function of tube type, such that certain 25wpc tube amps can generate more ambient heat than a 75wpc amp just because of the type of tubes it uses?

I didn't take these questions into account when purchasing the VSi55, but we may put together a 2nd system for another room and I may take this into account for that purchase. And as others have done, having a nice Class-D amp for the June-Sept period is also a possibility. Thanks in advance!