I think that we sometimes forget that we are answering these posts while looking in our own mirror.
In my initial response, I said "It probably depends on how hot of a room you can take before feeling uncomfortable.".
I am 6'2" and unfortunately weigh 300 lbs. I'm warm at work when the temperature is 70 degrees, while others are in their offices with their space heaters running.
So when I get hot and am sweating in my 10' x 12.5' room, it's isn't an enjoyable experience for me. I have no problem concerning the electric bill, but I personally can't see pretending to be enjoying myself knowing that I have a great amp if I'm miserable sitting there listening.
Chuck