Pass X600 Will it heat my room too much ??

It's not the heat you have to worry about, your electric bill will go through the roof if you leave the on all the time.

Putting it simply.
The X series is class A/B
The XA series is class A
A XA150 will heat up the room much more than a X600 will. Even though the X600 is far more powerful and probably larger.

Cheers George

I have yet to encounter an amp that put out so much heat that it bummed me out. I have a couple of tube amps with 4 output tubes per channel. One operayes in class A, I am ccertain about that. I freely admit that the tubes get very, very hot and put out plenty of heat I just don't position myself close to the amps, I am at least 8-10 feet away. The rooms seem to handle it well.
I hope I haven't jinxed myself because I now have to downsize post divorce. My new place is quite small she got the house (they always get the house!!)

Mechans

I hope your divorce wasn't over this hobby. I want a pair of XA100.5's and my wife is not happy about it. So if I want them I am just going to have to pull the trigger and see how it goes.

By the way I had an INT-30A in my listening room for a couple of weeks which is about the same size as yours and has a cathedral ceiling and from a heat perspective I never even knew it was on.

I run a pair of XA60.5's (220 watts each) 24/7 in a 25x16x8 foot room and never notice any increase in room temperature!

My electric bill for these amps is $25/mo.

Hot tube amps with fans is another matter.