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.
Radiator (heating)
Denison Olmsted of New Haven, Connecticut, appears to have been the earliest person to use the term 'radiator' to mean a heating appliance in an 1834 patent for a stove with a heat exchanger which then radiated heat. In the patent he wrote that his invention was "a peculiar kind of apparatus, which I call a radiator". The heating radiator was invented by Franz San Galli in 1855, a Prussian-born Russian businessman living in St. Petersburg. In the late 1800s, companies, such as the American Radiator Company, promoted cast iron radiators over previous fabricated steel designs in order to lower costs and expand the market.