@Adriano78,
Energy consumption and AC usage varies greatly depending upon where a person lives. I am from the San Francisco Bay Area, and my husband is an air conditioning technician, yet we didn't have a unit in our house, because of the temperate weather in our area, and ceiling fans sufficed during the 10 hot days per year. We now live in Atlanta, where the summer temperatures average over 90F/32C, and the pollen count is extremely high. Most people, who didn't have allergies before usually get them when they move to Atlanta (like I did). Almost everyone has AC and in their homes (often central AC units), and they use them during most of the time that they are home, and keeps their windows and doors closed. Smart thermostats and allergy medicines are extremely popular.
In St. Lucia, most don't have it, but more homes are getting AC, and mini-split systems in the bedrooms are the most common installation. For locals, air conditioning is used at bedtime when open windows and a whirling fan are unable to do anything to lessen the affects of the thickly humid stagnant air that makes you sweat so much that the bed linen becomes damp.
It's been my observation, that guests from North America and Europe use air conditioning equally. I've also noticed that they had usage of the dishwasher and laundry appliances in the self-contained apartment.
I believe that people who live in very urban or rural areas tend to be the most energy aware, because they regularly experience outages or limited availability. Plus, the rates usually are higher than the national average. Those who live in states or municipalities that don't have a high energy tax or levy tend to be less concerned about their electricity usage, because their rates a pretty low.
I don't doubt what you said about your American family members heavy electricity usage, but I am willing to bet that my Northern California family members probably use the same amount as a European family who lives in a similar climate. A lot depends upon where you live, how energy conservation has been taught, encouraged and enforced.