I have a smaller house, but use more power, probably because of terrible insulation in a 50 year old house. I also have gas heat. My average electrical usage is ~2000 kWh/month. Tesla sized a 20 KW system for my house with 3 PWs recommended, but I went with only 2 PWs to save money. In 2 years, I've generated almost exactly what my house uses, but since the biggest generation is in the afternoon when I cannot use all of it, I sell back about 15% of the power I generate and that is with storing some in the batteries. Without the PWs, I would be selling back about 45%.
While the payback of PWs is not as good as the solar payback, I would still go with their recommended 3 PWs. I've always been sorry that I didn't get the extra PW. For one, I could stop worrying about multiple day blackouts and, in times like this summer when I've been getting as high as $5/kWh for excess power, the PW payback would be quicker.
For power, I really like Tesla Electric, but with multiple EVs, it might work out better with a free night plan and find something that provides a good rate on selling your excess. My bills since going with Tesla Electric have generally been less than $5/mo and they have been significantly negative this summer (-$150 credit so far). Tesla Electric seems to offer the best buyback plan. If they finally offer the $25-30 EV charging plan this fall, Tesla Electric might be the sweet spot.
