Solar Sizing by TNB Bill for Semi-D and Bungalow Homes: Malaysia Guide 2026

Is it worth it with a high monthly bill?

Whether solar pays back depends on how much of the generation your house actually uses during daylight, not on the bill figure alone. TNB’s official example for a 5 kWp domestic system assumes 800 kWh of monthly usage, 75% of generation self-consumed, and works out to savings of RM238.81 per month (RM2,865.72 per year) against a bill of RM345.89 without solar. ^[source] Those are TNB’s stated assumptions — your result moves with your daytime load, your final price and the export credit, so treat this as a worked example to copy, not a promise.

For a smaller self-use-fit design versus using more of the roof, request both layouts against the same bill period, daytime load and equipment/work scope. Compare added monthly generation with daytime use and export credit actually applicable to the account, and include incremental system cost. Ask for usable roof faces, orientation and shading for each layout; choose the larger option only when its extra usable or credited energy justifies its extra cost, not simply to “future-proof” against a tariff change.

The sizing question hides a second question: panel capacity (kWp) and inverter capacity (kWac) are different numbers, and the ATAP connection limit counts the inverter one. ^[source] A proposal that only says “10kW solar” is not specifying which number it means — ask before comparing.

12kW vs 72kW — which one is my house?

Peak panel capacity is stated in kWp; inverter output is stated in kWac. The Solar ATAP guidelines use kWac for the domestic connection limit. ^[source] Without the system details behind a quoted figure, it cannot be read as the right capacity or the actual generation for your house. Start from the bill, then let the proposal show both numbers separately.

Application role and comparing written quotes

For a domestic Solar ATAP application in Peninsular Malaysia, the applicant appoints a SEDA-registered PV Service Provider (RPVSP) to submit the application through eATAP. This describes the filing role; it is not an endorsement of installer quality or a promise of approval. ^[source] When comparing installation proposals, ask for the same fields in writing; you choose how many proposals to request.

Before paying, ask each provider to state:

1. Who files the application — the RPVSP that will submit the Solar ATAP application and what that filing scope includes. ^[source]
2. The proposed system — full panel brand/model and count, total panel kWp, and inverter model and output kWac. Ask for supply phase and the basis of the proposal; kWp and kWac are different figures.
3. Price and work — a dated total and quote-validity date, with installation, roof mounting, wiring, labour and fees listed as included or excluded.
4. Generation assumptions — ask the provider to state the assumptions behind its generation and self-use estimate. Compare proposals on the same written assumptions; TNB’s example is not a forecast for your roof.
5. Responsibilities and warranties — who supplies equipment and who installs it; request the document, issuer, scope, start date, exclusions, claim contact and any labour/shipping costs for each warranty. Do not assume all contracts divide responsibility in the same way.
6. Site work — ask the quote to describe the mounting method, work included or excluded, and who handles an installation issue for your home; do not assume identical costs for different roofs.

Before comparing two prices, align the models, panel kWp and inverter kWac, work scope, fees and quote-validity period. If a detail is missing, ask for it in the written proposal before deciding. If weighing an upfront payment against a loan or instalment plan, request the cash price, deposit, rate and fees, term, and total payable in writing. Compare that total against the same generation, self-use and export assumptions; do not assume monthly savings will cover the instalment.

Read also: solar hub | home battery solar | BM version