How hot is hot when moving from class a/b to to a or tubes?

I have all Audio Research Reference gear… nearly 40 tubes. 140 watts per channel. I just went over and held my hand around one of the power tubes… it was slightly hot… touching it, it felt very warm… maybe hot… but you would have to work to get it to burn you. The preamp has 7 tubes is slightly warm. On top of unit.

I have a large room, never noticed it warming the room… but when it 100+ degrees out my air conditioner is on. It does nothing to warm the room.

I seriously doubt my listening amounts to more than a couple dollars a month. 
 

‘’The design does determine the heat. Some designers use the tubes to their max and will generate more heat and shorter tube life. My tube life is over 3,000 hours per set.

To me this is completely a non-issue compared with the incredible sound quality you get with a great tube amp.

@mpoll1 

Another thought might be to get a tube preamp and a SS class A amplifier or two.  The tubes in the preamp can last 10,000+ hours and throw off a lot less heat.  You can get the tube sound without the fuss and expense of output tubes. Also many companies are making hybrid amps that have driver tubes, solid state output.  I have a couple of amps that are exactly opposite of that.  They have solid state drivers and tubes for the output.

All the best.

Its all relative. For sure SS Class A runs hotter than A/B. Digital amps run cooler. Tube amps run usually hotter than all three, except perhaps for ghdprentice, but, for example I run a 40wt tube amp 10 to 12 hours a day. Puts out a bit of heat but really doesn't warm my house much as far as I can tell, nor does my A/C bill run high. The up side is in the winter I keep my house at 68 degrees and if my hands get chilly I just walk over and put them on the transformers, not the tubes!).  My expense is I go thru a quad of tubes every year and that can be a bit pricy, but it was worse when I ran a big tubed amp and it was two quads. The enjoyment I get from music greatly exceeds the small additional costs involved in running the equipment.  

Also, on warm up. It depends. I could talk about the warm up on the previous versions of Audio Research preamps, in great length. But I really don’t notice much of any with the current Reference models. While earlier warm ups were only 10 to 15 minutes. I’m just not hearing any with contemporary amps and preamps. It used to really stick out… you could not help hear it… but today I am just not hearing it. There may be a little… but if so, really subtle.

I live in a suburb of Memphis TN, gets very hot here during the summer. I have 2 tube integrated amps in my main system which is in a 25x19 foot room so smaller than yours mpoll1. One of the integrated amps is 845 tube based; the other 7189A/EL84M .  It doesn't matter what the season , neither, and most specifically the 845, never leave me feeling that they are heating up the room; nor that the AC runs more in the summer because one or the other are on. Likewise,  I have a KT88 integrated amp in my upstairs family room with similar footprint and that also doesn't heat up the room. Net net, your room is bigger than either of mine and I wouldn't think twice about the "heat issue" in your case.  Cost wise I haven't ever attempted to size up the utility cost factor whether using tubes, or class A/B amps; I'm more interested in musical enjoyment.  I will agree that the tube amps sound better after 30 minutes or so, and I begin listening after allowing the tubes to initially warm up for 10 minutes or so.