How to Read an Electricity Bill: Units, Telescopic Slabs & AC Costs
Learn how to read electric meter bills in Kerala (KSEB bimonthly telescopic slabs) and the Gulf (DEWA, SEWA, SEC), calculate air conditioner costs, and reduce monthly power bills.
By Muhammed Nuhman P • Last reviewed: October 2026 • 7 min read
- 1 Unit of Electricity = 1 Kilowatt-hour (kWh) = 1,000 Watts running for 1 hour.
- KSEB Telescopic Slabs (Bimonthly): Up to 250 units bimonthly, power is billed at progressive tier rates. Crossing 250 units triggers non-telescopic billing, where all units are charged at a much higher uniform rate!
- Gulf Bills (DEWA / SEWA / SEC): Gulf utilities bill monthly with residential consumption slabs starting from 23 to 38 fils/kWh, plus mandatory housing municipality fees.
- Air Conditioners: A 1.5-ton split AC running 8 hours a night consumes 10 to 14 units daily, accounting for 60% to 75% of your total household electricity bill.
1. What is an Electricity Unit (kWh)?
Your digital electricity meter records power in kWh (Kilowatt-hours). One unit of electricity is consumed when appliances totaling 1,000 watts run for exactly 1 hour.
Universal Consumption Formula:
Units (kWh) = (Watts × Operating Hours per Day × 30 Days) ÷ 1,000
| Appliance | Power Rating | Daily Hours | Monthly Units (kWh) |
|---|---|---|---|
| 1.5 Ton Inverter AC (24°C) | 1,200 W (average) | 8 hours | 288 Units |
| Water Geyser (Heater) | 2,000 W | 1 hour | 60 Units |
| Frost-Free Refrigerator | 250 W (cycles on/off) | 24 hours | 55 Units |
| Ceiling Fan (BLDC) | 28 W | 14 hours | 11.8 Units |
| Standard Ceiling Fan | 75 W | 14 hours | 31.5 Units |
| LED Television (55-inch) | 100 W | 5 hours | 15 Units |
2. KSEB (Kerala) Bimonthly Billing: The 250-Unit Cliff
In Kerala, the Kerala State Electricity Board (KSEB) reads domestic meters once every two months (bimonthly). Understanding their tariff structure is vital because crossing the 250-unit threshold results in a substantial financial penalty:
- Telescopic Billing (0 to 250 Units Bimonthly): Each slab is charged at its own low progressive rate (e.g. 0–80 units at ~₹3.25/unit, 81–160 units at ~₹4.05/unit, etc.).
- Non-Telescopic Billing (Above 250 Units Bimonthly): Once your bimonthly consumption hits 251 units, telescopic progressive benefits disappear, and all units from unit 1 are charged at elevated fixed slab rates!
Consuming 248 units bimonthly might cost you approximately ₹1,150. Consuming just 6 extra units (254 units) shifts your entire consumption into the non-telescopic category, jumping your bill to over ₹1,850. Keeping consumption under 250 units bimonthly saves hundreds of rupees every billing cycle.
3. Understanding Gulf Electricity Bills (DEWA, SEWA & Saudi SEC)
If you live in Dubai, your DEWA bill combines electricity, water, and the Dubai Municipality Housing Fee:
- Electricity Slab Tariff:
- Residential Green Slab (0 – 2,000 kWh/month): 23 fils per kWh.
- Orange Slab (2,001 – 4,000 kWh/month): 28 fils per kWh.
- Red Slab (Above 6,000 kWh/month): 38 fils per kWh.
- Fuel Surcharge: A variable monthly fuel adjustment component (typically 5 to 6.5 fils per kWh) passed through from global fuel costs.
- Municipality Housing Fee: Equal to exactly 5% of your annual tenancy contract, divided equally into 12 monthly installments on your utility bill.
Setting your air conditioner thermostat to 24°C instead of 18°C or 20°C reduces AC compressor power consumption by 18% to 24% over an entire month. Inverter AC compressors run at ultra-low wattage once 24°C is reached, avoiding heavy electricity surges.
Frequently Asked Questions
What is the Connected Load on my KSEB bill?
Connected load is the total wattage of all electrical appliances installed in your house. If your connected load exceeds the permitted limit on your sanction letter (e.g., you installed three new 2-ton ACs without notifying KSEB), you may be penalized with additional monthly fixed charges.
Why is my electricity bill higher during summer months?
When outdoor ambient temperatures exceed 40°C in the Gulf or 35°C in Kerala with high humidity, AC compressors must work double the hours to extract heat from rooms, causing daily kWh consumption to soar even if usage hours remain identical.
Estimate your household power bills using our Electricity Cost Calculator.