How to use the solar net billing calculator
- 1 Enter your system size in kW.
- 2 Enter your monthly units.
- 3 Enter the share of solar used directly during the day.
- 4 Enter the import rate, export rate and system cost.
Worked example
A 10 kW system for a home using 900 units, with half of the solar used directly. The system produces about 1,200 units: 600 used directly and 600 exported. You import 300 units at Rs 60 and earn Rs 10 per exported unit, so the bill falls from Rs 54,000 to about Rs 12,000, saving about Rs 42,000 a month.
Getting the most from net billing
Under net billing, units you import are charged at the normal tariff and units you export are bought back at a much lower rate. That changes how you should use solar.
- Use power in the daytime: run washing machines, water motors, irons and ACs while panels are producing, so you avoid buying units at the full rate.
- Size for self-use: a system much bigger than your daytime use mostly earns the low export rate.
- Approval: you need a bidirectional (green) meter and DISCO approval before exporting.
Size the system with the Solar System Calculator, and see today's bill with the Electricity Bill Calculator.
Features
Net billing
Imports and exports are priced separately.
Self-use matters
Using solar directly saves the full retail rate.
Payback
Years for savings to cover the system cost.
When to use it
Going solar
See savings under the current rules. Size the system with the Solar System Calculator.
Changing habits
See the benefit of running appliances in the daytime. See today's bill with the Electricity Bill Calculator.
Battery decisions
Compare storing power with exporting it. Shift appliances with the Appliance Running Cost Calculator.
Sizing
Avoid a system much larger than your needs. Financing solar? Compare the Home Loan Calculator.
Related Bills and Energy tasks
Frequently asked questions
What is net billing?
Under net billing, units you import from the grid are charged at the normal tariff, while units you export are bought back at a lower rate set by the regulator.
How is it different from net metering?
Under old net metering, exported units offset imported units one for one. Net billing pays a lower rate for exports, so self-use becomes more valuable.
What is the export buyback rate?
The buyback rate is set by NEPRA and the government and has changed over time. Enter the current rate from your agreement or DISCO.
Do existing net metering users change?
Existing agreements usually continue under their old terms until they expire. Check your agreement.
How can I increase savings?
Run ACs, pumps, washing machines and irons during sunny hours so more solar is used directly.
Do I need a green meter?
Yes. A bidirectional (green) meter is installed by the DISCO after approval.
How long does approval take?
Usually several weeks, depending on the DISCO and paperwork.
Is a battery worth it under net billing?
Batteries let you use more of your own solar at night, but they add cost and need replacement every few years.
What is the payback period for solar under net billing?
With high grid tariffs, many homes recover the cost in two to four years, depending on self-use and system price.
Does exporting more increase savings?
Each exported unit earns only the buyback rate, so using solar directly saves much more than exporting it.
What happens to excess credits?
Rules for carrying forward or paying out excess export credits depend on your agreement and DISCO.
Who approves a net billing connection?
Your local DISCO, following NEPRA rules for distributed generation.
Results are estimates based on the official rates linked above. Confirm important figures with the issuing authority or a qualified adviser before you act on them.
Built and reviewed by Hamza Farooq, founder and lead developer
· Last updated
· How we check our tools
· Report a problem