Tamil Nadu Electricity Bill Calculation 2026: Why Your June TNEB Bill May Be Higher

On Tamil Nadu electricity bills, one unit = one kilowatt-hour (kWh) — the energy used when a 1 kW load runs for one hour.

Examples (approximate):

Takeaway: Two identical flats on the same street can differ by hundreds of units because of AC hours, geyser type, WFH setups, and old fridges — not because the discom “picked” them.

Rates below reflect the subsidised domestic schedule widely published for FY 2025–26 after the state absorbed the July 2025 hike. Verify on the official calculator before paying or disputing.

When bi-monthly consumption is 500 units or less

When bi-monthly consumption is more than 500 units (telescopic)

Crossing 500 units moves you into telescopic billing; free allowance becomes 100 units, not 200.

Why June hurts: A bill dated June often covers high-use April–May. One extra week of daytime AC after a heatwave can push you from the ≤500 table to telescopic slabs — the rupee impact is non-linear.

The 500-unit cliff (illustrative)

Estimates only — run your exact units on the TNPDCL calculator.

The gap between 480 and 520 units is far wider than “40 extra units × one rate” because the free-unit rule and slab stack change.

These are worked examples for Chennai’s IT-corridor apartment belt — not your exact bill. Substitute your meter reading.

Scenario A — 3BHK flat, Perungudi, ~946 units bi-monthly

Profile (illustrative): Two inverter ACs running most nights, WFH laptops, double-door fridge, RO pump, balcony lights, lift share billed separately.

Add electricity duty (~5%), meter rent, and any rounding — then compare to your PDF. Do not treat ~₹6,633 as the amount due until you run the official tool.

Scenario B — Same flat, adding a third AC for a guest room

If the third AC adds ~120 units over the same bi-monthly window (illustrative), total use moves from ~946 to ~1,066 units. The extra units fall largely in the ₹12.15 slab once you are already deep in telescopic billing — a ₹1,000+ swing on energy charges alone is plausible before duty. This is why residents say “one more AC doubled the bill” — it is slab math, not a metering error by default.

Scenario C — Navalur ground-floor shop on commercial tariff

A street-facing boutique or café is typically not LT I-A domestic. Commercial low-tension tariffs have different slabs, fixed charges, and no 200-unit free block. A shopkeeper comparing their bill to a neighbour’s flat bill is comparing two tariff books. Check the tariff category code printed on the bill header.

Scenario D — Sholinganallur apartment common supply (lifts + pumps)

Associations with more than 12 units and lifts often have a domestic common supply meter. Press reporting on the July 2025 order noted common-area energy charges moved to ₹8.80/unit (from ₹8.55) with fixed cost ₹110/kW (from ₹107/kW) — costs are split across flats via maintenance invoices, not always visible on your home meter. Ask the RWA for the common meter reading and the per-flat split formula.

Scenario E — Terrace booster pump (600 W) running long hours

A 0.6 kW pump running 6 hours/day for 60 days ≈ 216 kWh bi-monthly — before any AC. OMR blocks with irregular metro water timing often see pumps on timers; a stuck float switch can add hundreds of hidden units.

1. Open the official calculator: tnebnet.org — Tariff Check → choose Domestic tariff and Bi-monthly cycle (use Monthly only if your bill says the cycle is under 35 days).
2. Enter consumed units exactly as printed on the bill — not your monthly guess.
3. Note the tariff category on the PDF (LT I-A for standard homes). If it says commercial or common supply, domestic slabs do not apply.
4. Compare line items: energy charges, duty, meter rent, arrears, subsidies, and round-off — the calculator may not list every legacy adjustment on old connections.
5. Cross-check the meter: note the present reading and previous reading; difference should match billed units (subject to MD / average rules on some connections — rare on vanilla domestic).
6. Photograph the meter if you dispute; raise a complaint on TNPDCL helpline / section office with consumer number, not just Twitter.
7. Apartment residents: confirm whether DG backup or STP loads are on your flat meter vs common meter.

Use this table when your June bill looks wrong — fill from your PDF and portal.

• Set AC to 26 °C with closed doors — each degree lower can add measurable load over 60 days.
• Service AC filters before May; dirty coils raise kWh per hour.
• Replace ageing fridges/geysers — over 10-year appliances are common in older Adyar stock; OMR flats often inherit previous tenant loads.
• Put pumps on timers and fix float switches — silent 24×7 pumps are a classic 200-unit leak.
• Compare LED retrofit for balcony and parking lights if you own the circuit.
• Shift heavy laundry/dishwasher to off-peak if you are on time-of-day pilots (check bill — most domestic LT I-A is still flat energy slabs).
• Rooftop solar — if you are above 600 units bi-monthly, see our guide on PM Surya Ghar in Chennai (net metering and subsidy caps apply).
• Pre-monsoon wiring check — see discom safety advisory before water meets bad earthing.

Branding note: Colloquially Chennai still says “EB bill” or “TNEB”; legally the discom is TANGEDCO and the consumer portal is TNPDCL. Use the names on your bill when filing complaints.

• OMR — Perungudi to Sholinganallur — corridor hub for apartment-town context.
• Consumer topic — bills, apps, and household costs.
• Chennai rooftop solar subsidy (PM Surya Ghar) — when slab bills push you toward PV.
• Pre-monsoon electrical safety — wiring before squalls.
• Chennai local news — latest city desk stories.