Residential air conditioning was close to zero percent until after WWII.

https://www.smithsonianmag.com/smithsonian-institution/unexpected-history-air-conditioner-180972108/

Household AC grew to 50% by 1970 and 90% by 2017. It grew from 88% in 2011 to 91% in 2019.

http://www.freeby50.com/2011/08/percentage-of-homes-with-air.html

https://www.census.gov/programs-surveys/ahs/data/interactive/ahstablecreator.html?s_areas=00000&s_year=2017&s_tablename=TABLE3&s_bygroup1=1&s_bygroup2=1&s_filtergroup1=1&s_filtergroup2=1

https://www.eia.gov/consumption/residential/reports/2009/air-conditioning.php

https://www.bloomberg.com/news/articles/2019-07-10/why-we-always-fight-over-air-conditioning

More New Homes Built with Air Conditioning

The increased level of air conditioning is largely driven by the increased level of air conditioning included in new home construction.

https://www.eia.gov/consumption/residential/reports/2009/air-conditioning.php

More New Homes Built with Air Conditioning

https://www.bloomberg.com/news/articles/2019-07-10/why-we-always-fight-over-air-conditioning

Air conditioning demand varies significantly by region/climate. AC use increased from 75-99% in the South, from 60-90% in the Midwest, from 50-85% in the northeast and from 40-60% in the West. AC demand varies based on peak temperatures, the number of days at peak temperature, the number of hours per day at peak temperature and the humidity (felt temperature). San Francisco, Portland and Seattle rarely “require” AC, even though their residents could afford this service.

https://usafacts.org/articles/91-of-households-nationwide-have-air-conditioning-44-of-those-in-seattle-do/

https://www.bloomberg.com/news/articles/2019-07-10/why-we-always-fight-over-air-conditioning

https://www.iea.org/data-and-statistics/charts/percentage-of-households-equiped-with-ac-in-selected-countries-2018

https://howtoguide.org/europeans-can-live-without-ac/

https://www.smithsonianmag.com/smithsonian-institution/unexpected-history-air-conditioner-180972108/

The US, Japan and Korea lead the world in households with air conditioning. China and Saudi Arabia are representative of moderate-income nations with relatively high AC usage. Most other nations, including the wealthier European nations, remain at very low rates of AC adoption (10%). This is a “good news” item for personal comfort, but not so good for energy consumption.