What you need to know
Simple solar payback equals net installed cost divided by modelled annual bill savings. Net cost should include the confirmed system price and subtract only confirmed incentives. Annual savings should separate self-consumed solar from eligible export value and disclose generation, tariff, degradation and maintenance assumptions.
Key takeaways
- Do not calculate payback from panel capacity alone.
- Use approved or realistic incentives—not an unconfirmed headline rebate.
- Separate self-consumption value from export-credit value.
- Compare a simple payback with a longer cashflow view that includes degradation and maintenance.
01
The simple solar payback formula
Simple payback = net installed cost ÷ modelled annual savings. If a system costs RM30,000 after confirmed incentives and is modelled to save RM4,200 in year one, the simple payback is about 7.1 years. This example is illustrative and is not a promise of price or savings.
Simple payback is easy to understand, but it does not show what happens after payback. A 20- or 25-year view can show the effect of module degradation, inverter servicing, tariff changes and financing cost.
02
What belongs in annual savings?
Annual generation is only the starting point. The model should split solar into electricity consumed in the home and electricity exported under the applicable regional programme. The value of those two streams may differ by grid and programme.
- Expected first-year generation based on the roof and local solar resource.
- Daytime self-consumption percentage.
- Eligible export quantity and the assumed credit treatment.
- Current tariff and any stated escalation assumption.
- Module degradation and system availability.
03
Why two identical systems can have different ROI
A home with daytime air-conditioning, a home office or regular appliance use can consume more solar directly than an empty house. Roof direction, shade, tilt, ventilation and cable runs also change generation and installed cost.
Regional policy matters just as much. Peninsular Malaysia, Sarawak and Sabah have different incentive, metering and export arrangements. A nationwide headline payback that ignores the address is not a reliable proposal.
04
Questions to ask before accepting an ROI number
Ask for the generation report and inputs behind the result. A professional proposal should let another informed person reproduce the broad answer. It should also show what happens if generation or self-consumption is lower than expected.
- Is the incentive confirmed, or merely assumed?
- What percentage of solar is used directly in the home?
- What export rate and programme period were used?
- Are degradation, maintenance and financing included?
- Is the savings figure year one, average annual or lifetime total?
Straight answers
Frequently asked questions
What is a good solar payback period in Malaysia?+
There is no universal number. A useful result depends on region, tariff, incentive, system price, roof yield and usage. Compare proposals using the same disclosed assumptions.
Does a bigger solar system always produce a better ROI?+
No. Larger systems can export more of their generation or add capacity that the household does not value as highly. Right-sizing usually produces a more defensible return.
Should battery savings be included in solar ROI?+
Only when the model clearly shows battery cost, usable capacity, operating strategy, replacement assumptions and the value of resilience or shifted energy. Solar-only and solar-plus-battery cases should be compared separately.
Is estimated solar savings guaranteed?+
No. Actual savings vary with weather, household consumption, equipment performance, downtime, tariff and programme rules. A model is a decision tool, not a guarantee.
Official and primary sources
Policy and product information can change. These were reviewed on 19 July 2026; confirm current eligibility and specifications before making a purchase decision.