Air conditioning
Modern air conditioning emerged from advances in chemistry during the 19th century, and the first large-scale electrical air conditioning was invented and used in 1902 by US inventor Willis Carrier. The introduction of residential air conditioning in the 1920s helped enable the great migration to the Sun Belt in the United States.
Central heating
Franz San Galli, a Prussian-born Russian businessman living in St. Petersburg, invented the radiator between 1855 and 1857, which was a major step in the final shaping of modern central heating. The Victorian cast iron radiator became widespread by the end of the 19th century as companies, such as the American Radiator Company, expanded the market for low cost radiators in the US and Europe.