You're mistaken. In most of Europe thermodynamics are still very much applicable, lack of AC doesn't mean your hot computer doesn't make your room warmer anymore, so extra heat from an old inefficient computer still ends up in your house, raising your ambient temperature and making you uncomfortable (in the summer) regardless if you have AC or not.
Lack of AC doesn't make the "hot computer making my room warm" problem go away, it just makes it a better case for investing in thermally efficient electronics because you have no AC to vent it out with.
Yes, but we tend to focus on passive cooling rather than active cooling - your comment was all about active cooling and the extra costs thereof, and passive cooling techniques do not imply an extra power cost.
But yes - modern lower power hardware (Apple Silicon, lower power AMD Zen, etc) can be drastically faster than older hardware, at significantly lower power - and massively lower total power consumption for work done.
You can get wins here by making sure even modern hardware is running in the more power efficient part it's perf/watt curve - for example, ECO mode on modern AMD hardware (105W+ to 65W, for instance), reducing the board power limit on GPUs when doing compute (~420W to 225W, for most efficient on my 3090!), etc. You lose remarkably little performance by doing so.
You're mistaken. In most of Europe thermodynamics are still very much applicable, lack of AC doesn't mean your hot computer doesn't make your room warmer anymore, so extra heat from an old inefficient computer still ends up in your house, raising your ambient temperature and making you uncomfortable (in the summer) regardless if you have AC or not.
Lack of AC doesn't make the "hot computer making my room warm" problem go away, it just makes it a better case for investing in thermally efficient electronics because you have no AC to vent it out with.