Your result
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Enter your values, then click Calculate result.How this calculator helps
Estimate how long energy savings may take to recover the upfront system cost. This simple-payback view subtracts a yearly maintenance allowance from annual savings and clearly separates recovery time from investment return.
How to Size a Solar System in Pakistan
Calculate solar kW, panel count, inverter capacity and realistic generation from your own electricity use.
Read the complete guide →How to use it
- 1
Enter the complete installed cost after any included equipment and labour.
- 2
Estimate monthly savings from actual consumption and a conservative production scenario.
- 3
Add recurring maintenance and compare several tariff and degradation assumptions.
Formula and methodology
Net annual saving = monthly bill saving × 12 − annual maintenance. Simple payback years = installed cost ÷ net annual saving.
Uses editable energy demand, sunlight, equipment and loss assumptions. It is a planning model rather than a site survey or electrical design.
Worked calculation example
A PKR 1,200,000 system saving PKR 30,000 monthly with PKR 20,000 yearly maintenance produces PKR 340,000 net annual saving and roughly 3.5-year simple payback.
How to interpret your result
Estimate simple solar payback time from installed cost, monthly savings and annual maintenance allowance. Read the main result together with the supporting values rather than treating one number as a guarantee. The disclosed method is: Net annual saving = monthly bill saving × 12 − annual maintenance. Simple payback years = installed cost ÷ net annual saving.
Input guide
Enter the complete installed cost after any included equipment and labour.
Estimate monthly savings from actual consumption and a conservative production scenario.
Add recurring maintenance and compare several tariff and degradation assumptions.
Scenario comparison
| Scenario | What it demonstrates |
|---|---|
| Worked baseline | A PKR 1,200,000 system saving PKR 30,000 monthly with PKR 20,000 yearly maintenance produces PKR 340,000 net annual saving and roughly 3.5-year simple payback. |
| Tariff changes check | Future electricity pricing can shorten or extend recovery time. |
| Equipment replacement stress test | Inverter or battery replacement can materially increase lifecycle cost. |
Common mistakes to avoid
- Ignoring tariff changes: Future electricity pricing can shorten or extend recovery time.
- Overlooking equipment replacement: Inverter or battery replacement can materially increase lifecycle cost.
- Failing to test self-consumption: Export compensation and the portion used on-site affect realised savings.
Check the result against equipment datasheets, a site survey and a written design from a qualified solar professional.
What can affect the result?
Tariff changes
Future electricity pricing can shorten or extend recovery time.
Equipment replacement
Inverter or battery replacement can materially increase lifecycle cost.
Self-consumption
Export compensation and the portion used on-site affect realised savings.
Limits of this estimate
Simple payback ignores financing, inflation, discounted cash flow, tariff changes, degradation, taxes and major component replacement.
Sources and review information
Frequently asked questions
Is the solar payback calculator free?＋
Yes. SolvePilot tools are free, work in your browser, and require no account.
Does SolvePilot store my values?＋
No. Calculations run locally in your browser and the values you enter are not sent to a server.
Should I treat the result as an exact bill or quotation?＋
No. Results are informed estimates. Final charges can vary because of taxes, tariffs, lender terms, usage patterns, or provider rules.
How can I improve the accuracy?＋
Use recent values from your own bill, statement or institution, review every assumption, and confirm important results with the relevant official source.
Does simple payback include financing or equipment replacement?＋
No. Financing, tariff changes, degradation, inverter or battery replacement and resale value require a fuller cash-flow model.