You can switch, but check three things first. One, can you go back: Type 2 users can ask to return to the normal rate after using TOU for the required minimum period, while existing Type 3 and Type 4 users who move to TOU cannot return to their old rate, at both PEA (Provincial Electricity Authority) and MEA (Metropolitan Electricity Authority). Two, the switching charge is a one-time payment that differs by utility and meter type; confirm the amount with the utility for your area. Three, whether your bill goes down or up depends on whether your factory's units and its highest power draw fall more in the On Peak or the Off Peak period.
The energy rates and demand charges in this article are PEA low-voltage figures for the September 2026 billing period, for these two lines only; they exclude Ft, VAT and other items on the bill. PEA's TOU switching charge excludes VAT, while MEA's includes VAT.
| Your current type | Move to TOU | Return to the old rate |
|---|---|---|
| Type 2, normal rate (2.1) | Yes, it is an optional rate | Yes, once the required minimum period is completed |
| Type 3, existing user, normal rate (3.1) | Yes | No, at both utilities |
| Type 4, existing user, TOD (4.1) | Yes | No, at both utilities |
Can you return to the old rate after moving to TOU?
Type 2 users can try TOU and go back once they have used it for the required minimum period. Existing Type 3 and Type 4 users cannot go back after moving, so for them it is a one-time decision.
Before asking whether it pays off, you need to know whether the door you are about to walk through closes behind you. The rules for changing rates differ between small businesses and medium–large businesses, and your type is determined by your maximum power demand (see how the types are separated in How much does a factory pay per unit of electricity, and why does it differ from factory to factory).
For Type 2 (small business), the TOU rate, or 2.2, is an optional rate. Once you have used it for the required minimum period you can ask to return to the normal rate, 2.1. This minimum period is a condition for returning; it does not mean the switch pays off by that point. MEA customers must notify the Metropolitan Electricity Authority of their intention before choosing rate 2.2. What this means for you: a Type 2 user can try TOU, watch the actual bills for a while, and then decide whether to stay or go back.
For existing Type 3 users on the normal rate (3.1) and Type 4 users on TOD (4.1), it is different. You can move to TOU (3.2 or 4.2), but once you have chosen it you cannot return to the old rate, at both PEA and MEA. PEA's wording is “rate type 3.2 is permitted, subject to payment of the charges set by the Provincial Electricity Authority; however, once chosen, the customer cannot return to rate type 3.1”. MEA's wording is “3. Customers on rate 3.1 may choose rate 3.2 by notifying the Metropolitan Electricity Authority of their intention”. In plain terms: you can move, it costs money, and there is no undo button.
What this means for you as an existing Type 3/4 user: this is a one-time decision, so think it through fully before applying, covering the two-period energy charge, the demand charge and the switching charge you must pay. The next three sections walk through each of these line by line.
- TOU
- An electricity tariff charged according to the time of use, short for Time of Use; the energy charge does not have a single price all day.
- Normal rate
- The conventional tariff that charges one energy price no matter what time of day the power is used (for small-business users it is tiered by the number of units consumed).
- TOD
- The older tariff for large businesses with a single energy price, but with the demand charge split and calculated by time period.
Is the TOU energy charge really cheaper than the normal rate?
Not always. The TOU On Peak period is more expensive than the normal rate and the Off Peak period is cheaper, so whether your bill goes down or up depends on which period most of your factory's units fall into.
TOU splits the energy price into On Peak and Off Peak periods, and holidays count as Off Peak (the clock times are in TOU On-Peak / Off-Peak: which hours are they). The normal rate charges one price regardless of when the power is used. The statement “TOU is cheaper” is therefore only half true: it is true only for the units used during Off Peak.
Look at the figures for a medium business (Type 3) at low voltage: the normal-rate energy charge is 3.1751 THB/kWh, while TOU charges 4.3297 THB/kWh for On Peak and 2.6369 THB/kWh for Off Peak. TOU's price opens out into two sides, one higher than the normal rate and one lower. Every unit you use is assigned to one side or the other according to the time it is used. For this set of Type 3 low-voltage figures, MEA uses the same values.
Small businesses (Type 2) follow the same direction. The difference is that the Type 2 normal rate is tiered: the more you use, the higher the per-unit price in the later tiers. TOU has no tiers but splits the price by time period. The table below places them side by side so you can compare in pairs: the On Peak period is higher than every tier of the normal rate, and the Off Peak period is lower than the first tier.
| Business size | Rate type and period | Energy charge, low voltage, PEA, September 2026 billing period |
|---|---|---|
| Small (Type 2) | Normal rate, first units, up to 150 kWh/month | Normal rate, first units · 3.2484 THB/kWh |
| Small (Type 2) | Normal rate, next units, up to 400 kWh/month | Normal rate, next units · 4.2218 THB/kWh |
| Small (Type 2) | Normal rate, units beyond the second tier | 4.4217 THB/kWh |
| Small (Type 2) | TOU, On Peak period | 5.7982 THB/kWh |
| Small (Type 2) | TOU, Off Peak period | 2.6369 THB/kWh |
| Medium (Type 3) | Normal rate, all units | 3.1751 THB/kWh |
| Medium (Type 3) | TOU, On Peak period | 4.3297 THB/kWh |
| Medium (Type 3) | TOU, Off Peak period | 2.6369 THB/kWh |
How to read the table: do not just compare the lowest price against your current price. Compare in pairs: the normal rate against On Peak as one pair, and the normal rate against Off Peak as another, then ask yourself which pair most of your factory's units pile up in. This article does not calculate how many Off Peak units you need for the switch to lower your bill, because the answer depends on each factory's operating pattern.
Energy charge per unit, low voltage, medium business (Type 3) — normal rate compared with TOU On Peak and Off Peak
It is like two kinds of expressway toll. The first charges a single flat price at every hour. The second charges more than the flat price during rush hour but less outside it. Which one costs you less is not decided by the price sign, but by when you get on the expressway.
Factories whose units fall mainly in the On Peak period
- Those units are charged at TOU's On Peak price, which is higher than the normal rate
- After moving to TOU, this part of the energy charge becomes more expensive, not cheaper
- For Type 3/4 users, the demand charge in the next section also has to be considered
Factories whose units fall mainly in the Off Peak period
- Those units are charged at TOU's Off Peak price, which is lower than the normal rate
- Units still used during On Peak continue to be charged at a price higher than the normal rate
- The larger the share of Off Peak units, the larger the portion that gets the lower price
Type 3 and Type 4 users must also look at the demand charge line
Type 3 and Type 4 bills carry a demand charge on top of the energy charge, and TOU applies this line only during On Peak, so you must compare both lines, not the energy charge alone.
Type 2 users do not have this line, but Type 3 and Type 4 users pay a demand charge based on the highest power the factory draws from the grid each month. What makes TOU different is that the normal rate uses the highest value across the whole month, while TOU uses only the highest value during the On Peak period (the measurement mechanism is explained in What is the demand charge and how is it calculated).
At low voltage, a medium business (Type 3) on the normal rate pays a demand charge of 221.50 THB/kW, while TOU charges 210.00 THB/kW and only for the On Peak period. What this means for you: a factory whose highest power draw occurs outside On Peak benefits on this line even though the On Peak energy charge is more expensive, because the peak draw during Off Peak is not counted under the TOU rate.
Existing Type 4 users on TOD need to compare one level more carefully, because the structures are different: TOD charges a single energy price in every period but splits the demand charge into On Peak and Partial Peak, whereas TOU splits the energy charge by period and charges demand only for On Peak. Moving from TOD to TOU therefore swaps which line is split by period; it is not simply one line getting cheaper or more expensive.
- Demand charge
- A monthly charge based on the highest power the factory draws from the grid during the billing month, a separate line from the energy charge that is based on the number of units.
- Partial Peak
- The name of a time period that the TOD rate uses to calculate the demand charge separately, distinct from the On Peak period.
| Business size | Item | Price, low voltage, PEA, September 2026 billing period |
|---|---|---|
| Medium (Type 3) | Normal rate, demand charge | 221.50 THB/kW |
| Medium (Type 3) | TOU, demand charge, On Peak period | 210.00 THB/kW |
| Large (Type 4) | TOD rate, energy charge, all periods | 3.1751 THB/kWh |
| Large (Type 4) | TOD rate, demand charge, On Peak period | 332.71 THB/kW |
| Large (Type 4) | TOD rate, demand charge, Partial Peak period | 68.22 THB/kW |
| Large (Type 4) | TOU, energy charge, On Peak period | 4.3297 THB/kWh |
| Large (Type 4) | TOU, energy charge, Off Peak period | 2.6369 THB/kWh |
| Large (Type 4) | TOU, demand charge, On Peak period | 210.00 THB/kW |
So there are two questions about your own factory to answer before deciding: in which period do most of your units fall, and when does your power draw peak? If both are outside On Peak, these two lines point the same way. But if most units are Off Peak while the peak draw occurs during On Peak, the two lines pull in opposite directions. And because existing Type 3/4 users cannot go back after moving, look at both lines across several months of bills before applying.
On PEA: how much should you set aside for the TOU selection charge?
PEA charges a one-time fee for choosing TOU, categorised by your actual meter type. All amounts exclude VAT and are not part of the monthly bill.
The switching charge is not hidden in the monthly bill; it is a service charge for choosing the TOU rate, paid once when you apply. PEA's service-charge schedule is categorised by meter type, took effect from February 2026, and all amounts exclude VAT. If you are not sure which type your meter is (low voltage with how many phases, CT-metered, or high voltage), ask your local utility office first; do not guess from the size of your business.
| Meter type | PEA TOU selection charge, paid once (excluding VAT) |
|---|---|
| Low voltage, 1 phase | 3,300 THB |
| Low voltage, 3 phase | 3,750 THB |
| CT-metered, low voltage, 1 phase | 3,500 THB |
| CT-metered, low voltage, 3 phase | 3,550 THB |
| High voltage, 22–33 kV | 4,050 THB |
| High voltage, 69 kV and above | 19,000 THB |
One caution: this schedule does not spell out which customer types it applies to. The switching condition for existing Type 3/4 users (3.1 to 3.2 or 4.1 to 4.2) says only that charges set by PEA must be paid, without stating which item or how much, and the Type 2 condition is worded the same way. So use this table to frame your questions, then confirm with your local PEA office whether your case is charged according to this schedule, and do not add VAT yourself and treat that as the amount due.
On MEA: how much should you set aside for the TOU switching charge?
MEA charges for switching to TOU without changing the meter size, categorised by meter size, and all amounts include VAT, so they cannot be compared directly with PEA's figures.
MEA categorises the switching charge differently from PEA: by meter size (amperes for low voltage and kVA for medium voltage), not by number of phases. The figures shown are for the case where the meter size is not changed, and every amount already includes VAT, so do not add VAT again. If your switch also requires a change of meter size, this set of figures does not cover it and you need to ask MEA separately.
| Meter size | MEA charge for switching to TOU for Type 2 customers, without changing the meter size (including VAT) |
|---|---|
| Low voltage, below 50(150) A | 3,350 THB |
| Low voltage, 50(150) A and above | 4,600 THB |
| Medium voltage, 300–15,000 kVA | 4,600 THB |
Because the VAT basis differs (PEA excludes it, MEA includes it) and the meter categories are different, do not put the two utilities' figures side by side and conclude that one is cheaper. Whichever area you are in, use that utility's table.
MEA's procedural condition for existing Type 3/4 users moving from 3.1 to 3.2 or from 4.1 to 4.2 is that they must notify their intention and pay for the TOU meter first. MEA's Type 2 customers can choose between paying for the meter upfront or paying an additional monthly meter service charge (other differences between the two utilities are covered in PEA vs MEA: do business electricity rates differ). So there are two questions to ask the utility before applying: which row of the table your meter falls in, and whether your case requires a change of meter size.