If I spend this much on solar, what output and savings might I get?

How it works

Understand the estimate

Divide your budget by the installed cost per kWp to estimate panel capacity. Multiply that by annual generation per kWp, the share used at home and the electricity rate to estimate yearly savings on grid electricity.

Make it more accurate

Roof direction and angle, tariffs, export rules, inverter size and the times you use electricity all affect savings.

The starting figures are examples. Replace them with the rates or prices that apply to you.

How much of the solar electricity will you use?

Solar generation is not the same as bill savings. Electricity produced when you cannot use it may have little financial value without permitted export compensation or storage. Equipment sizing, roof direction, shading, financing, maintenance and tariff escalation can all affect the outcome.

Example: A 5 kWp array with an illustrative annual yield of 1,500 kWh per kWp generates around 7,500 kWh a year. If the household can use only 60% of that generation, 4,500 kWh offsets grid purchases. At R3/kWh that is R13,500 a year in electricity charges saved before expenses.

Before relying on the estimate

Do not treat a simple payback figure as an investment guarantee. Ask an installer to compare expected generation with your electricity use at different times of day. Read the warranty exclusions too.

For more detail, read our calculation and editorial standards. Use your own bill, receipt or quote for current prices. These tools do not fetch live rates.