The average home uses 1.5kw of energy. Traditionally, homes connect to a city power grid that sells them electricity from generating plants. Customers are charged per "kilowatt hour," (as in, 1kw * 1 hour, a unit of energy equal to 3,600,000 joules). I have heard prices quoted as low as 5 cents per KWH, and as high as 20 cents per KWH. Assuming 10 cents per kwh, the average home's bill is 36 cents per day.
However, with a few clever technologies, these homes could easily power themselves. This would prove a major advantage if the grid ever shuts down, as it does during earthquakes, hurricanes, tornadoes, and other disasters, or as it sometimes does by accident. (Sometimes areas of the grid spike with power and must be shutdown to avoid destroying equipment. Sometimes the shutdown is an accident, but it takes a while to start up again.)
Solar power varies by insolation. In the United States, western Arizona gets the most sun, collecting 6.5 KWH per square meter of panel per day. A region near the northern section of the Idaho/Montana border gets the least at 3 KWH per square meter per day. If homes in these two regions wanted to power their homes by solar panel, backed by large batteries, the home in Arizona would need 6 m^2 of panel, but the home in Idaho or Montana would need 12 m^2 of panel.
Diesel powered generators are common for emergencies. They are not frequently used, as they produce only about 400 watts, require constant fueling to run, and are noisy, stinky, and inconvenient. Still, many people have them because it's better than not having power.
Radioisotope power really comes in handy. An organization, the Idaho National Laboratory, currently makes radioisotope electric generators for spacecraft. These consist of cylinders, about 6 feet long and perhaps 1 foot in diameter, which produce a slow, constant source of electricity from the heat of nuclear waste. Each cylinder produces 300 watts of power with no radiation. (Aparently, the waste is mostly alpha emitters. Alpha radiation could not make it through the outer jacket. In fact, if you held an alpha-emitting metal in your hand, your skin would block all the radiation. Just don't eat it.) At 300 watts each, 5 cylinders would power the home, and could easily be stashed in a basement corner and forgotten.
Wind power is possible in some areas, but only where the wind blows reasonably consistently. I can think of only two places where this holds, one is in South Dakota, one is in California, and both are somewhat free of housing at the moment. Wind power would use quite a lot of space, so probably isn't a good idea for housing power.
Prior experiments have proven that home generated power is perfectly compatible with grid power. In fact, most regions require the utility company to buy back power you produce should use produce more electricity than you use. In such a case, your electric meter literally runs backwards. The utility companies complained bitterly, and most have significantly slowed the rate at which the meter turns backwards, but it does indeed turn backwards and does indeed reduce your bill. In most of these regions, they had little reason to complain. California passed such laws in hindsight of a massive brownout problem due to a lack of capacity, and the utility company's argument looked very stupid indeed in light of that.
Since most grid power in the United States is powered by coal and hydroelectric power, conserving this has a major environmental impact. Coal smoke smells, and lower demand means less burned coal.