It is true that the tube amps do run hot... about half of their standby power is actually in filament supplies!
Big tubes have big filaments. That is why they can deliver current pulses of several amps with ease.
Regarding the total power dissipation, it is about 500W per unit. Which is about 1700 BTU. From there a calculation can be made in terms of air conditioner load.
Tube life in units like VK-60 is not really an issue. There is some percentage of power tubes that fail early due to internal arcing, about 3-4% overall, but average tubes typically last several years.
There is also no thermal stress on internal components, they run very cool, due to design derating and strong chimney effect. Therefore after 15 years of production we are still not seeing any amps failing due to overheating. Usually the problems are related to random component failures, or foreign objects in the units - heavy accumulation of dust and pet hair among the most common.
Regards,
Victor Khomenko