Home emergency generators are usually powered by gasoline, which must be properly handled as well.Generator sizes vary. Common units can be from 8 to 14 horsepower and capable of handling from 4,000 to 8,400 watts (including starting surge requirements). Prices may range from $800 to $3,000.Connecting a generator to the main electrical supply for your house requires the services of a qualified licensed electrician. Installing the connection and switch (as explained below) can cost from $600 to $1,000.Before connecting the generator to your household circuit, notify your electric cooperative.NEVER try to power a house by plugging the generator into a wall outlet, a practice known as "backfeeding." This is an extremely dangerous practice that presents an electrocution risk to utility workers and neighbors served by the same utility. It also bypasses some of the built-in household circuit protection devices.