As a counter-example, I grew up in Miami. We had neither A/C nor a furnace, only electric space heaters for when it got to the 40s and upper 30s. (Our house was

As a counter-example, I grew up in Miami. We had neither A/C nor a furnace, only electric space heaters for when it got to the 40s and upper 30s. (Our house was built in the 1950s, before A/C, so built in the older style with high ceilings, many windows, a crawl space for even more cooling, and no insulation. When it was 40 outside, it was 40 inside.) We did have a neighbor who contracted with a propane company to fill a residential tank, which was used for heat and cooking. But that wasn't common in the neighborhood. In Tallahassee, the places I rented didn't have gas, only electricity. Eg, pulling up rental housing in Tallahassee, https://www.rentrange.com/tallahassee-fl/o-3316-calumet-nice-family-house-for-rent-washer-dryer-hookups--o-32311/for-rent/ https://www.rentrange.com/tallahassee-fl/o-3316-calumet-nice... says it has "Electric heating". Searching for Atlanta, I found http://www.cbs46.com/story/21444870/atlanta-fallen-tree-leaves-residents-without-lights-and-heat http://www.cbs46.com/story/21444870/atlanta-fallen-tree-leav... which says "'Fallen tree leaves Atlanta residents without lights and heat' ... "My house used electric heat so it's cold". Rather than be anecdotal about it, I found "Space Heating in U.S. Homes, by Climate Region, 2009" from http://www.eia.gov/consumption/residential/data/2009/#sh http://www.eia.gov/consumption/residential/data/2009/#sh . Of the 19.1 million homes in the "Hot-Humid climate region", 12.4M use electricity, 4.6M use natural gas, 1.4M have no heat, 0.5M use propane, and the others (fuel oil, wood, etc.) are too small to be meaningfully reported. There is an apparent conflict between your observations and this survey (and with my own observations from living in Florida).