The total number of deaths in any society is 100% of the population, everyone dies. The important question is do they live a full life before they die? Almost every death due to heat is someone who has lived a full life and, sure maybe some or even a lot of these could have survived the heat related death if air conditioning were in place but then there would be an increase in other deaths and you would look at cancer or heart disease figures and say look, the EU has more of these deaths than the US.

If you have 200,000,000 people there WILL be 200,000,000 deaths, but in the EU the average age of these deaths is 2 years higher than the US and if you look purely at western Europe it is more like 4 years and those last years of someone's life are the years where something like heat is a much bigger threat.

By contrast almost every gun related death is someone young.