Off-grid solar sizer

How this sizes your system

We pull monthly solar production for your exact point from NLR PVWatts, the national lab model utilities and installers use, then size to the darkest month of the year instead of the annual average. An off-grid system that covers December covers July for free. The battery bank is sized for three days of cloudy weather at LiFePO4 depth-of-discharge limits, the same method the paid Homestead Plan uses.

The three household profiles assume wood or propane for heat, cooking, and hot water, the classic off-grid load shape. Electric heat or an EV charger changes these numbers more than anything about the land does.