Solar Basics
How to Calculate Electricity Bill Savings with Solar
By SaveBill Editorial Team. Last updated 2026-11-10.
Estimating savings is arithmetic you can do yourself with three numbers: your monthly units, solar generation and your tariff.
Step 1: Estimate generation A system produces about 96 kWh per kW per month under standard assumptions. A 3 kW system gives about 288 kWh.
Step 2: Compare with usage If you use 300 units, solar could offset most of them. Savings come from the units you no longer buy from the grid.
Step 3: Apply your tariff Multiply avoided units by your average rate. Tariff slabs mean the highest-priced units are often the ones solar removes first, so use your own bill.
What solar does not remove - Fixed and demand charges - Night-time grid use without batteries - Taxes and duties as applicable
Example method Avoided units x tariff, minus yearly maintenance, gives yearly savings. Compare that to your net cost using the ROI calculator.
Common mistakes Assuming a zero bill, ignoring shading, and using a tariff from another state or category.
FAQ ### Why is my actual saving lower than estimated? Shading, soiling, weather and usage changes all matter. ### Where can I find my units? On your electricity bill under consumption in kWh.
Sources and further reading
Figures here are illustrative and use stated assumptions. Check official sources for policy details.