Solar System Sizing Guide for Malaysian Terrace Houses: kWp vs Bill
In this guide
Size from actual use and site data
A monthly RM total or roof area alone cannot establish the right array size. Before comparing proposals, collect the kWh and dates from recent bills, supply phase, daytime load profile, roof or ground-mount constraints, shading, and any critical backup needs. Ask the designer to show panel DC capacity (kWp) and inverter AC output (kWac) separately.
To choose between a self-use-fit design and filling the usable roof, request both options on the same load and equipment scope. Compare the extra kWp with monthly generation, daytime self-use, exported energy and any credit that actually applies; ask each estimate to state roof face, orientation and shading. Choose the larger array only when the added usable energy and export terms justify its added cost—roof area or the RM bill alone is not a reason to maximise panels.
| Input | What to record | Why it matters |
|---|---|---|
| Electricity use | Actual kWh, bill dates and daytime usage | The bill amount alone cannot determine energy use or system size. |
| Supply | Single- or three-phase account; inverter kWac | ATAP capacity checks use inverter AC output, not panel kWp [source]. |
| Roof/site | Usable area, orientation, shading, structure and access | A site survey is needed before a layout or panel count can be stated. |
| Proposal | Equipment, generation assumptions, fees, exclusions and warranties | Comparable written scope makes offers assessable. |
Dated installer-advertised price references
These compiled installer display bands were captured on 29 September 2026. They describe advertised configurations, not a quote, a recommended capacity or a current offer; ask for the same written scope and confirm today’s terms.
| Approximate panel array | Advertised band |
|---|---|
| 5 kWp | RM15,000–30,000 [source] |
| 6.6 kWp | RM17,999–38,000 [source] |
| 8 kWp | RM20,499–45,000 [source] |
The bands span different installer offers and do not establish which size fits a terrace roof or household load.
ATAP limits are not a sizing recommendation
The cited domestic inverter limits are 5 kWac single phase and 15 kWac three phase. A Connection Confirmation Check route with a recorded RM1,000 fee applies above the standard limits; this does not mean approval is automatic [source]. Ask the provider to confirm the applicable route for the actual supply and design.
What the TNB example does and does not show
The cited TNB worked example uses 5 kWp and 800 kWh monthly consumption; its reported monthly generation and bill figures belong to that example and its assumptions [source]. Do not scale those numbers linearly to another roof or bill. Ask the designer for a written generation scenario based on the property’s orientation, shading, equipment and actual load.
Before signing, check the current provider registration where applicable, panel and inverter models, kWp/kWac, roof and electrical work, fees, exclusions and warranty responsibilities.
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Frequently asked questions
What information is needed to size a terrace-home solar system?
Use actual bill kWh and dates, daytime load, supply phase, roof/site survey, and a written design that separates panel kWp from inverter kWac.
Does a monthly bill amount establish system size?
No. A bill total includes tariff components and billing days; use the actual kWh and site-specific load/design data.