http://www.slate.com/articles/arts/culturebox/2011/07/a_history_of_air_conditioning.html https://www.pri.org/stories/2014-10-04/how-air-conditioning-got-ronald-reagan-elected-president
Silly. Those same people would have voted the same even if air conditioning hadn't been invented and they hadn't moved south. Reagan won in the "rust belt" states as well as the south, places where the Democrats had held a commanding presence. Trump did the same.
Their votes wouldn't have been in the South. The States he won in the North wouldn't have changed. You do understand how the Electoral College works, right?
So the northern states wouldn't have lost population and electoral college votes and the southern states wouldn't have gained population and electoral college votes. You do understand how the census works, right?