Malaysia Solar Calculator: What It Can and Cannot Tell You
Estimate home solar size from your TNB bill (T10 method)
Enter billed kWh, billing days, a gross generation target and a site-specific yield assumption to estimate kWp.
Same method and bounds as the T10 solar sizing calculator at /solar/kalkulator-bil-tenaga-solar-en/ — four inputs from your bill or a site assessment, no defaults. The yield assumption must come from a site assessment or quote. Checked 2026-11-12 — Betul ke x? (betulkex.com)
In this guide
Need a solar sizing calculator or a quote worksheet?
Use the T10-method calculator at the top of this page to convert bill kWh, billing days, a gross-generation target and an assumed site yield into a preliminary kWp estimate; the full T10 guide walks through the four inputs in detail. The worksheet below collects quote and savings assumptions; neither the calculator nor the worksheet calculates ROI. For wider home, shop and factory comparisons using proposal assumptions, see the solar hub and scenario calculator.
For a home estimate, keep the bill kWh and billing days beside the target and yield assumption you plan to use. Large premises need load-profile and maximum-demand analysis; a household bill calculator is not the right sizing method. A displayed seller price band can be a rough screen, not a quote or guaranteed market price [source].
| Question | Useful input or method | Boundary |
|---|---|---|
| Home system size | Bill kWh, billing days, generation target and site-yield assumption [source] | Domestic connection thresholds: 5 kWac single phase / 15 kWac three phase; larger systems require a Connection Confirmation Check (CCC), not an automatic prohibition [source] |
| Premise sizing | Load profile and maximum demand | Non-domestic route; not a household-bill calculation |
| Estimated cost | Use a dated advertised band only as a screening reference [source] | Ask the provider to state the required site assessment and written quote |
| Savings and payback | Applicable account tariff and daytime self-consumption [source] | ATAP export credits apply to the energy component in the same bill month; unused credit does not roll forward [source] |
Four inputs and a checkable example
The sizing method accepts energy use from 1 kWh, bill periods of 1–62 days, a generation target of 1–100%, and a site-yield assumption above zero and no more than 10 kWh per kWp per day [source]. Example: 450 kWh over 30 days, an 80% generation target and 3.5 kWh/kWp/day yield gives a 360 kWh monthly target and about 3.4 kWp [source]. TNB’s example also uses 3.5 sun-hours per day in its illustrative generation arithmetic [source]. Use actual bill kWh and billing days, not memory.
Check the output before relying on it
Check the connection threshold: the cited domestic guide sets 5 kWac single phase and 15 kWac three phase; a larger installation is routed to a Connection Confirmation Check (CCC), not automatically prohibited [source]. Do not equate a calculator’s DC kWp estimate with the AC kWac connection threshold; ask the provider to state both and explain the design assumptions. The sizing tool does not reconstruct the electricity bill. A separate savings scenario must use the applicable account tariff and billing month: the cited RM0.4443/kWh and RM0.5443/kWh are composite energy + capacity + network references for lower- and higher-usage account categories, separated at 1,500 kWh per month. They are not sequential marginal blocks, energy-only rates or a complete bill formula. AFA is a dated adjustment, so September 2026 is not a rate for another month [source] [source] [source] [source] [source] [source].
The 3.5 kWh/kWp/day in the registered arithmetic is a hypothetical input, not a universal site yield. TNB’s separate example uses 3.5 sun-hours/day as an assumption [source]. A calculator cannot see roof orientation, shade, structure or your daytime load. Those affect usable generation and self-consumption. An illustration using a 5 kWp example, displayed installer-price inputs and a SuRIA rebate is arithmetic over dated inputs, not an expected customer outcome [source] [source] [source]. Ask for a written, itemized quote after site review.
Four-input T10 worksheet to prepare a quote request
Copy the four inputs from a bill or a stated site assumption. If site yield has not been assessed, write unknown; do not treat a T10 example as a reading from your home.
| Input/output | Your value | Source / date / status |
|---|---|---|
| Bill energy use (kWh) | ____ | Bill for selected period: ____ |
| Bill start/end dates and number of days | ____ / ____ / ____ days | Copy from bill |
| Gross-generation target (%) | ____ | Your screening choice, not a savings target |
| Assumed site yield (kWh/kWp/day) | ____ | Provider/source and date: ____; if not assessed, write unknown |
| Normalized 30-day kWh | ____ | T10 method output |
| Gross-generation target (kWh/30 days) | ____ | T10 method output |
| Approximate panel capacity (kWp DC) | ____ | Arithmetic output; not kWac, self-consumption or money |
Keep proposal context separate: property type ____; general Peninsular Malaysia location ____; supply phase ____; TNB account category as shown on bill ____; panel kWp DC ____; inverter kWac ____; CCC check if applicable ____; quote date ____; complete installed total and itemized lines ____; scope/exclusions ____; warranties ____; payment stages ____. Mark unknowns rather than guessing. The kWp result is not self-consumption, AC inverter size, a future bill or money saved. The T10-method calculator at the top of this page runs the same arithmetic; this guide does not change its logic.
After the worksheet: request a site-specific proposal
If you are planning a new installation for a landed home in Peninsular Malaysia, use the Verdant referral button on this page to request a proposal and ask Verdant to confirm site fit, design and the application process. The referral does not establish eligibility, CCC approval, price, generation or savings. Read the paid-referral disclosure and privacy notice shown in the referral section; personal details are entered on Verdant’s site. For an existing system, battery service, equipment-only purchase or business premises, contact the relevant installer/utility directly; this referral route does not expand those scopes [source].
Two dated examples, not forecasts
| Example and record date | Registered input/calculation | How to read it |
|---|---|---|
| T10 method record, 28 September 2026 | Hypothetical 450 kWh over 30 days; 80% gross-generation target; assumed 3.5 kWh/kWp/day yield → 360 kWh gross target and about 3.4 kWp DC | Invented inputs to check arithmetic; not user data, self-consumption, a design or savings [source] |
| TNB domestic example, captured 29 September 2026 | 5 kWp × 3.5 hours × 30 days = 525 kWh estimated monthly generation | TNB illustration assumption; not expected site output for a particular home [source] |
For a bill comparison, use the same account category and bill month. RM0.4443/kWh and RM0.5443/kWh are composite energy + capacity + network references for different usage categories, excluding AFA; they are not sequential marginal rates or a full bill formula [source] [source] [source]. The domestic AFA threshold is temporarily 800 kWh through 31 December 2026, then returns to the 600 kWh baseline from 1 January 2027; the AFA rate also follows the bill month [source] [source].
Read next: home solar sizing calculator · large-system sizing · installation costs · solar hub
Frequently asked questions
Why enter kWh instead of the bill amount?
Account tariff categories, bill components and monthly adjustments affect ringgit charges; kWh is the energy measure used for sizing. The cited TNB example estimates output from capacity and assumed sun-hours [source].
Does a calculator predict my savings?
No. It screens system size. Savings depend on tariff, monthly adjustments, site output and how much generation you use while it is produced; export credits are limited to the same bill month [source].