The heat of tubes...

There are really two issues: tube life and room comfort. To assure long tube life, you need to have at least a foot of clearance above the amp for ventilation. I remove the top plate from the amp when in use for extended periods. This helps the amp run cooler, extends tube life and improves the sonics. Next, I have two very quiet ceiling fans. Works well enough.
I live in New Orleans and we have an expression: It's not the heat, it's the stupidity. (There are other expressions like a 12 step program consists of two six packs of Dixie.) You learn down here to simply accept that there's going to be some exposure to tropical weather. Rather than suffer emotionally we simply eat, drink, enjoy music, take it slow, wear light cotton clothing and shower a couple times a day. Keep 'em glowing and have yourself a party!

I live in Seattle, and most of the time tube amps keep the room warm enought during the Winter, Fall and Spring without turning the heat on. What happens during the summer? well between Aug 1 and Sep 1, I open the windows. Tube amps are great in this climate.

Hey, Paulg805, I'm in Seattle too! Love the climate here, though the grey winters get old quickly. Got tubes and keep most in the closet where they heat my shoes and motorcycle helmets. At work the space is pretty large so don't have much of a problem there. I can't recall who it was on another thread...but I thought it was an interesting solution: Someone had their amps hung in the rafters in the basement down below their listening floor with the wires coming up through the floor. This would work to warm a perhaps otherwise cool basement too! Sorry I can't recall who posted that one or I'd certainly give credit.

I bought some ball bearing totally silent box fans to circulate the air above my CJ tube amps.

The only draw back in locating amps in closets, below floors is that I enjoy looking at my Cary 805, as much as listening to them. Many of tube amp are work of art, KORA, CARY, AIR TIGHT ....