Some napkin math. AC roughly halves the extreme heat mortality rate for users. If France (~25%) achieves the air conditioning penetration of Canada (~65%), 40% of the population will achieve half the deaths, down 20%. So installing a Canadian level of AC in France could prevent on the order of (1k * 20%) 200 additional deaths.

France has ~30M households, so to get to Canadian levels they'd need an additional 12M installations. At €3k per installation that's €36B, or ~€180M per life saved.

Installing heat pumps would provide cooling and make heating more efficient, paying for itself, and preventing deaths from cold weather, which is deadlier than hot weather: https://www.sciencedaily.com/releases/2015/05/150520193831.h...

I think this only looks a part of the picture though. These pensioners or otherwise elderly citizens will eventually die regardless, and new residents will take their place in these housing units. We don’t consider not running power or water to residential units, and with climate change rapidly causing AC to switch from being a luxury to a requirement, I think this becomes a cost to keep the housing unit in service for the remainder of its service life.

So, if the cost will be spent regardless eventually, any cost delta for prioritizing units housing the heat vulnerable is the true cost in this context imho. Every household in Europe now needs AC (heat pump) for at least the next 100 years (assuming leading heat trajectory indicators) due to climate change. Therefore, subsidize and prioritize those most at risk in the near term.

I’m sure China can build and sell these to Europe as fast as Europe needs them, the variables to solve for are cost and installation logistics. France market for heat pumps is currently ~1M/units/year. Scale up.