I have a roof top solar system and a Tesla powerwall. Sun common installed it. Works great as a back up but it’s not capable of being completely off grid during winter months. I’m not super knowledgeable on what it would take to be totally off grid but probably a lot if you live a modern lifestyle. The main problem being the limited amounts of sun we get in the winter. Like I said depends on your lifestyle, needs and how you heat and cook in your home but you will most likely need a lot of batteries plus a large solar array to be completely off grid during the winter in VT. If you have a small cabin and just want the lights on it would be different. But using your dryer, refrigerator, wifi, tv and lights at the same time on an cloudy December day will require a lot of battery back up because the sun probably won’t provide enough energy to do it.