I live in the Caribbean so I don't need any extra heat, thank you. I use Class-D amps partially to avoid the waste head. Cooling is just as expensive as heating and local power generation costs are ridiculous.
I get my tube "fix" via pre-amps. The tubes get "uncomfortably warm" as opposed to hot. I also opted for a pre that allows me to bypass the tubes or even go completely passive, if I'm in the mood for "ultra accuracy".