Peak hours are 8am–10pm on weekdays only. Saturdays, Sundays, and every gazetted Malaysian public holiday (cuti umum) are off-peak for the full 24 jam — the single most under-used lever on TNB ToU. Here’s the exact sen/kWh delta, who qualifies, and how solar turns this structure into 30–50% extra savings.
Time-of-Use (TOU) tariff is a pricing structure where TNB charges different rates for electricity depending on the time of day. During periods when national grid demand is high — primarily weekday business hours — electricity costs significantly more. During quieter periods at night and on weekends, rates are lower.
TOU pricing replaces the traditional flat-rate system for certain user categories. Under flat-rate billing, you pay the same sen/kWh regardless of when you consume electricity. Under TOU, the same appliance running at 2pm costs more than the same appliance running at 2am.
The rationale is straightforward: TNB must maintain enough power plant capacity to meet peak-hour demand, which is expensive. TOU pricing incentivises consumers to shift discretionary loads — water heating, production machinery, EV charging — to off-peak windows, reducing strain on the national grid.
Indicative rates by tariff category. Confirm exact rates on your TNB bill or at tnb.com.my.
| Tariff Category | User Type | Peak Rate | Off-Peak Rate | Saving at Off-Peak |
|---|---|---|---|---|
| Tariff A | Residential | 21.8–54.6 sen/kWh | Flat rate (TOU pilot) | Pilot opt-in only |
| Tariff B | Small commercial | 43.5 sen/kWh | 20.0 sen/kWh | ~54% |
| Tariff C1 / E1 | Medium commercial | 50.8 sen/kWh | 22.4 sen/kWh | ~56% |
| Tariff C2 / E2 | Large commercial / industrial | 45.6 sen/kWh | 20.4 sen/kWh | ~55% |
* Rates are indicative for Peninsular Malaysia. Sabah (SESB) and Sarawak (SESCO) have separate tariff structures. Maximum demand charges apply additionally for E-tariff customers and are not shown here. Verify with your latest TNB bill.
Maximum Demand charges apply to most commercial TOU tariffs. These are fixed monthly charges based on your highest 30-minute power demand during peak hours. Solar panels reduce maximum demand by shaving the peak — this alone can save RM hundreds per month for larger commercial users.
TOU pricing applies automatically to commercial users and optionally to some residential accounts.
Solar panels generate electricity between roughly 7am and 6pm — which overlaps almost entirely with TNB’s 8am–10pm peak window. This is not a coincidence: the sun is most productive exactly when electricity is most expensive. Every unit of solar energy you self-consume during peak hours displaces grid electricity at the highest possible rate, maximising your savings.
Solar generation (amber) sits almost entirely inside the peak window (red), meaning every solar kWh displaces your most expensive electricity. Overlap is approximately 10 out of 14 peak hours.
Solar self-consumption replaces the most expensive grid units, maximising sen-per-kWh savings.
Solar shaves peak demand, reducing your contracted Maximum Demand charge each month.
Surplus solar exported earns credits that offset your off-peak nighttime consumption.
Adding battery storage unlocks a third layer of TOU savings on top of what solar alone delivers.
During daylight hours, solar panels power your home or business for free. You consume zero grid electricity at the expensive peak rate — directly reducing your bill.
Any solar energy you generate but do not immediately use can be stored in a battery. Alternatively, you can charge the battery from cheap off-peak grid electricity at night (20–22 sen/kWh) to use as reserve during peak hours.
After solar generation fades in the early evening (5–7pm), your battery kicks in to power consumption through the expensive peak window until 10pm — avoiding grid rates entirely during the costliest hours.
Combined savings example: A commercial building on E1 tariff with a 50kWp solar system + 100kWh battery can reduce its monthly TNB bill by RM8,000–15,000 versus no solar — with payback in 4–6 years and 20+ years of reduced energy costs thereafter.
The right tariff depends on your usage pattern — and whether you have solar.
| Scenario | Without Solar | With Solar |
|---|---|---|
| Heavy weekday daytime use | TOU costs more — peak rates apply all day | Solar offsets peak hours — TOU becomes a major advantage |
| Heavy nighttime / weekend use | TOU can save money — off-peak rates are much lower | Both tariffs work — solar still saves on daytime peak |
| Mixed 24/7 usage | TOU roughly similar to flat rate — depends on mix | TOU with solar is almost always superior |
| EV fleet charging | Schedule charging off-peak — TOU saves significantly | Day charging on solar + night on off-peak — maximum savings |
Common questions about TOU tariff and solar in Malaysia.
Yes. Under TNB's Time-of-Use tariff, Saturdays, Sundays, and gazetted Malaysian public holidays are classified as off-peak for the full 24 hours. Peak rates only apply between 8:00am and 10:00pm on weekdays (Monday–Friday). Off-peak therefore covers: 10pm–8am every weeknight, plus all 24 hours on Saturday, all 24 hours on Sunday, and all 24 hours on any TNB-recognised public holiday (e.g. Hari Raya, Chinese New Year, Deepavali, National Day, Christmas Day). This is the single most under-used lever for ToU customers — shift discretionary loads (EV charging, water heating, laundry, production batches) into these windows for maximum savings.
Commercial and industrial customers on TNB tariffs E1, E2, E3, and above are typically subject to maximum demand charges and may be offered TOU-based pricing. Residential customers on Tariff A are generally on flat-rate billing, though opt-in TOU pilot programmes have been introduced in selected areas. Contact TNB to check your eligibility.
Under TNB's standard TOU structure, peak hours run from 8:00am to 10:00pm on weekdays (Monday to Friday). Off-peak hours cover 10:00pm to 8:00am every night, plus all day Saturday, Sunday, and public holidays. These hours can vary slightly depending on your specific tariff category — always confirm with your TNB bill or the TNB website.
For commercial E1 tariff customers, peak energy rates are typically 50–70% higher than off-peak rates. For example, where peak energy may cost around 43–55 sen/kWh, off-peak can be as low as 20–25 sen/kWh. The exact differential depends on your tariff tier and contracted maximum demand.
Yes — significantly. Solar panels generate electricity during the peak window (roughly 8am–6pm, which sits entirely within peak hours). Every unit of solar self-consumed during peak hours displaces the most expensive grid electricity. A solar system on a TOU tariff typically delivers 30–50% better savings than the same system on a flat-rate tariff.
Not necessarily. Even without a battery, solar delivers strong TOU savings by offsetting peak-hour consumption. A battery adds a second layer of benefit: you can store surplus solar (or cheap off-peak grid electricity) and discharge it during the expensive peak window. The battery payback calculation depends on your peak/off-peak rate differential.
It depends on your usage pattern. Businesses with most of their consumption during weekday business hours (8am–6pm) often pay more on TOU without mitigation. But those same businesses benefit enormously once solar is added — because solar generates exactly during the peak hours they would otherwise pay the most for. Businesses with heavy night-shift or weekend operations may find flat-rate or a hybrid tariff more cost-effective.
Use our calculator to estimate how much you can save on your TNB bill with a solar system designed for your tariff, usage pattern, and roof.
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