Short, plain answers. Written to explain the arithmetic, not to sell.
Fictional company. Every figure on this site is an illustrative example.
3 minute read
A kilowatt is how fast energy flows right now. A kilowatt-hour is how much has flowed over an hour. A 1 kW heater running for two hours uses 2 kWh. Panels are rated in kilowatts-peak (kWp), a lab figure for strong light; your roof makes less in most hours.
3 minute read
Self-use is the share of your solar power you use yourself. The rest goes to the grid. Without a battery it is usually a third or so; it rises if you run appliances when the sun is out. This site assumes 30 percent for the no-battery case.
4 minute read
Look at the evening. If your home uses 4 kWh between six and ten at night, a 5 kWh battery with 90 percent usable capacity covers most of it on days the roof made enough. More than that sits mostly empty.
3 minute read
Roughly 5 m2 of unshaded roof per kWp. A south-facing slope gives the most; east and west give a flatter day. Shade from a single chimney can matter more than the tilt.
4 minute read
Find your yearly kWh figure, the price per kWh you pay and any fixed charges. Solar changes the kWh you buy; fixed charges stay.
3 minute read
Panels need little: occasional rinsing and a look at the monitoring app. Inverters are replaced earlier than panels in most systems. Ask any installer for the service plan in writing.