TNB Time-of-Use (ToU) Explained: How It Affects Your Solar Savings

Time-of-Use (ToU) is a tariff structure where the price you pay for electricity — and the rate you’re credited for exporting it under NEM — changes depending on the time of day. It’s a different pricing model from the flat, single-rate tariff most Malaysian households are used to, and it matters a lot once solar is in the picture.

Peak vs. off-peak, in plain terms

ToU splits the day into (typically) two bands:

• Peak period — daytime and early evening hours when grid demand is highest. Electricity costs more per kWh during this window.
• Off-peak period — nights and early mornings when demand is lower. Electricity costs less per kWh.

The exact hours and rates are set by TNB and revised periodically, so check the current rate card on TNB’s own site or with your installer rather than assuming last year’s numbers still apply — what doesn’t change is the underlying logic below.

Why this matters if you have solar

Solar panels generate during daylight hours — which, under ToU, is exactly the peak-priced window. That timing works in your favour in two ways:

1. Self-consumption during peak hours avoids the most expensive electricity you’d otherwise buy. Every kWh your panels supply directly to your home during the day is a kWh you’re not paying peak rate for.
2. Any exported surplus is credited at the peak-period export rate, which is typically the more favourable of the two ToU export rates — daytime is when your system is generating, so this is where most of your export naturally lands anyway.

The mismatch to watch for is the evening: once the sun goes down, your household draws from the grid again, often right as usage picks up for the night — and depending on the exact peak/off-peak boundary, some of that evening usage may still fall in the pricier window.

Where battery storage fits in

This is the scenario where a home battery starts to make financial sense on top of solar. A battery lets you:

• Store midday solar surplus instead of exporting it at the (lower) NEM export rate, then
• Discharge it during the evening peak window, avoiding the need to buy grid electricity at peak rates for those hours.

Whether that trade-off is worth the extra upfront cost of a battery depends on your evening usage pattern, the size of your solar surplus, and current battery pricing — it’s a case-by-case calculation, not a universal “yes.” Households with heavy evening usage (cooking, aircon, EV charging at night) see a stronger case for a battery than those whose usage is mostly during the day. See our full breakdown in do you need a solar battery in Malaysia?

Should you switch to ToU?

Whether ToU works in your favour — with or without solar — depends on when you actually use electricity. A household that’s mostly out during the day and heavy on usage at night may find flat-rate tariffs simpler and cheaper. A household with solar and meaningful daytime self-consumption is usually the clearest winner under ToU, since it’s designed around exactly that shift in behaviour.

The only reliable way to know is to check your own usage pattern against TNB’s current ToU rate card — or ask an installer to model it against your last 12 months of bills before you decide.

Compare SEDA-verified installers who can model your specific usage against current tariffs, or read our solar cost guide if you’re still sizing a system.