Is Switching to a TOU Meter Worth It? Run the Break-Even First (2026)
TOU makes Off-Peak power (nights/holidays) much cheaper, but On-Peak power (weekday daytime) much more expensive. Whether you WIN or LOSE depends on when you actually use power. This page runs the break-even, with a home that pays off and one that doesn't — so you decide from real numbers, not a guess.
Switching to a TOU meter is worth it only if you use most of your power — roughly 60% or more — during Off-Peak (nights 22:00–09:00 on weekdays, and all of Saturday–Sunday/holidays). That's because TOU prices Off-Peak below every normal tier (2.6369 THB/unit) but On-Peak (weekday daytime) above every normal tier (5.7982 THB/unit). Homes that charge an EV overnight or are power-heavy at night/on weekends usually win; homes that work-from-home or run AC all day usually lose. Before deciding, check the full TOU rate table against the normal home tariff, then run the break-even below.
How Does TOU Differ From the Normal Rate? (The Decision in One Line)
A normal meter bills by units on progressive tiers, regardless of time. TOU charges a different rate by time slot. The decision in one line: TOU makes night/weekend power much cheaper (2.64 THB/unit — below every normal tier) but weekday daytime power much more expensive (5.80 THB/unit — above every normal tier). You only win if you shift enough usage into Off-Peak. See the exact per-unit rates and windows in the TOU on/off-peak rate table, and check which days/hours are Off-Peak.
The rates above are energy charges before Ft (+0.1623 THB/unit, May–Aug 2026) and 7% VAT, which are added equally to both TOU and Normal — so they don't change WHICH tariff wins. The TOU monthly service charge is 24.62 THB.
When Does It Pay Off? The '~60% Off-Peak' Rule of Thumb
The simple logic: every unit you move to Off-Peak saves you roughly 1.3–1.4 THB, but every unit still On-Peak costs you about 1.8 THB extra. So the break-even sits at about 57% of units in Off-Peak — to be safe, people commonly say you need roughly 60% (approx.) or more of your power in Off-Peak before it starts to pay off (this is a rough rule, not an official figure; the real number depends on how many units your home uses and which price tier you sit in). And that's only the ENERGY break-even — it doesn't yet include the one-time meter-change fee. Light users (under 150 units/month) already pay a low normal rate (2.3–3.7 THB), so they usually should NOT switch.
Worked Examples — A Home That Wins vs One That Loses
Assume both homes use 500 units/month — the only difference is WHEN they use it (energy charge only; Ft/VAT are added equally to both). Compared against the normal >150-unit home tariff (3.2484 / 4.2218 / 4.4217):
Home A — WINS (night/weekend-heavy, e.g. has an EV)
70% Off-Peak (350 units) / 30% On-Peak (150 units):
• TOU = 350×2.6369 + 150×5.7982 = 922.9 + 869.7 = 1,792.6 THB
• Normal (500 units) = 150×3.2484 + 250×4.2218 + 100×4.4217 = 1,984.9 THB
• Saves about 192 THB/month → payback on the MEA 3,350 THB meter change is about 17–18 months, then pure saving (with overnight EV charging, Off-Peak often reaches 75–85%, shortening payback further).
Home B — LOSES (work-from-home / daytime-heavy)
30% Off-Peak (150 units) / 70% On-Peak (350 units):
• TOU = 150×2.6369 + 350×5.7982 = 395.5 + 2,029.4 = 2,424.9 THB
• Normal (500 units) = 1,984.9 THB (as above)
• TOU is about 440 THB/month MORE expensive → this home should stay on the normal meter; switching to TOU loses money every month and wastes the 3,350 THB change fee.
Want to run your own home's numbers? Plug them into the bill-calculation guide + calculator.
Who Should Switch / Who Should Not
A quick self-check before you decide:
Charge an EV at home overnight — EVs use a lot of power; charging after 22:00 every night pushes your Off-Peak share high — TOU is clearly worth it.
Heavy use late at night or on weekends — AC all night, home late, or power-heavy on Saturday–Sunday (Off-Peak all day).
Can timer your appliances — washer, dryer, water pump, heater and water heater set to run after 22:00 or on holidays.
Do NOT switch if: your home is power-heavy during weekday daytime (work-from-home, AC all day, elderly/young children home in the day), or you're a light user (under 150 units/month, where the normal rate is already low). For these homes, daytime is the On-Peak window where TOU is pricier than a normal meter — rooftop solar usually beats switching to TOU, because midday sun lines up exactly with On-Peak and self-generates to cut the units you'd buy at the most expensive rate. See net metering / selling back.
Meter-Change Cost + Payback
Switching your existing meter to the TOU rate carries a one-time cost. For the MEA (Bangkok–Nonthaburi–Samut Prakan), the service fee to change to the TOU rate (VAT included) is ~3,350 THB for an ordinary home meter (under 50(150)A) and ~4,600 THB for 50(150)–400A (the MEA cut this by over 50%, effective 16 Oct 2025). Once you know the fee, divide it by your monthly saving to get the payback — e.g. Home A above saves ~192 THB/month → payback ~17–18 months. For the PEA (provinces) the fee differs — call 1129 to confirm. All figures follow official announcements and can change; verify the latest via MEA 1130 / PEA 1129 / erc.or.th.
Can You Switch Back?
Yes — the TOU rate is voluntary. If it doesn't pay off, you can apply to switch back to the normal rate. But switching back also costs a service fee, so you shouldn't flip-flop; decide based on a stable usage pattern, not a single month's bill. The exact revert fee and any waiting period follow the utilities' announcements — ask MEA 1130 / PEA 1129. If you've decided TOU is worth it, see how to apply for a TOU meter.
About this page
Compiled by the CapSolar team, led by Frank Lee (Founder). The TOU rates and meter-change fees are checked against MEA announcements. The worked examples illustrate the principle; your real numbers depend on your usage pattern and user class. This page is general information, not personal advice — exact costs and rates follow the utilities' announcements; confirm with your local authority (MEA 1130 / PEA 1129 / erc.or.th) before deciding.
FAQ
Heavy daytime use? Solar may beat switching to TOU
Midday sun lines up exactly with the expensive On-Peak window. CapSolar will assess for free whether solar pays off for your home or building.