200 A 120/240 V, 60 Hz split-phase is the residential standard.
Where I am, whole-house AC isn't that common, although some people have heat pumps. I have a window unit that I use maybe 20 days out of the year, which is happy on a standard 120 V outlet. Forced-air is definitely the primary heating method, though it could be electric or gas. The only place you see LPG is out in the rural areas that are not served by CNG. Pellet stoves are gaining in popularity, and there are still a lot of people with old-fashioned wood stoves in the city and country. Oil has fallen out of popularity, although it's trying to make a comeback with "Clean" oil technology.
My duplex/apartment has a gas furnace, but an electric water heater and clothes dryer. During the winter, my gas bill has never been above USD $25, and the electric bill is usually around $50 (although that's included with my rent). The heat is used maybe 5 months out of the year, and even then not a lot. I have an old-fashioned on/off thermostat (non-programmable) so I only turn on the furnace when I am home and turn it off when I go to bed. It has a 100 A 120/240 service, which I assume was the original service to the house before it was split into two units. Original construction late 1940's or early 1950's, by my estimation.
