Overall it’s still going to be a net saving as people switch from electric/gas heat to heat pumps and AC is just those but running in reverse.
And, of course, insulation. The reason we got away without AC is due to generally very large thermal mass of the exterior, you shutter everything in the morning to keep the heat out and when the temperatures drop again you open everything and let the air cool everything down. Thing is: In those recent waves there were plenty of nights where the temperature didn’t really drop.