i have what is called a generator panel. it's mounted right beside the original panel and is fed from the original panel or a generator, i have what i call the critical curcuits mounted in it. furnace, hot water, well pump, sump pumps, central air, freezer, fridge and 2 wall sockets for lights. the panel works by a double throw, one to knock you off the grid the secound to connect you to the generator, double throw again to connect back to the grid. it rated for 30 amps but they do sell a 60 amp. when i experience a power failure i go down stairs and switch the panel to generator then go out to my garage connect the generator to the generator panel connector plug in the garage and flash up the generator. my generator is rated for 6500 watts. i've had this set up for 5 years now and no hickups. i might have went with the 60 amps but when you need the most electricity is on start up and nothing kicks on at the same time. this is the cheapest and legal way to go.