Electricity Bill: How Much Each Appliance Uses and How to Work It Out

Updated October 29, 2026

An electricity bill is the sum of what each appliance uses. You can work each one out with a simple sum — and in most Brazilian homes the electric shower and the air conditioner make up a large part of the total. Here is how to do the sum, how much common appliances use and where you can save.

1. The sum for each appliance

kWh a month = power (W) × hours on per day × days of use ÷ 1,000. Then kWh × tariff gives the amount in reais. The power is on the appliance's label or in the manual; fridges and air conditioners also show the monthly consumption on their Procel/Inmetro energy label.

The tariff changes from one distributor to another and with your state's taxes. The easiest way to find yours: on the bill, divide the total in R$ by the kWh used. The examples below use R$ 0.95 per kWh.

2. How much each appliance uses

Typical use in a home, at R$ 0.95 per kWh:

Appliance	Power	Use	kWh/month	A month
Electric shower	5,500 W	30 min a day	82.5	R$ 78.38
Air conditioner, 9,000 BTU	900 W	8 h a day	216	R$ 205.20
Fridge	150 W (average)	motor running ~8 h a day	36	R$ 34.20
TV	100 W	5 h a day	15	R$ 14.25
Computer	100 W	6 h, 22 days	13.2	R$ 12.54
Microwave	1,200 W	15 min a day	9	R$ 8.55
Iron	1,000 W	1 h, 8 days	8	R$ 7.60
6 LED bulbs	9 W each	5 h a day	8.1	R$ 7.70
Wi-Fi router	10 W	24 h a day	7.2	R$ 6.84
Washing machine	500 W	1 h, 12 days	6	R$ 5.70

Without the air conditioner, the example home uses 185 kWh, R$ 175.75 a month. With it on 8 hours a night, that goes to 401 kWh, R$ 380.95.

3. The electric shower: the biggest cost in most homes

A 5,500 W shower is 45% of the bill in the example: each hour it is on costs R$ 5.23. Taking 5 minutes off each day's shower saves 13.75 kWh, R$ 13.06 a month. The "summer" (warm) setting uses much less power than "winter".

4. Air conditioner and fridge

Air conditioner: the cost follows the hours it is on. Closed doors and windows, a clean filter and a setting around 23 °C let the compressor switch off more often. Inverter models usually use less.
Fridge: it is on all day, but the motor switches on and off — which is why the sum uses an average power. A worn door seal, a door left open and a fridge pushed against the wall make the motor work harder.

5. Tariff flags (bandeiras)

In months when generating electricity costs more, ANEEL switches to the yellow or red flag, which adds a fixed amount for every 100 kWh; the green flag adds nothing. The bill shows which flag applied and its amount. Example: with a surcharge of R$ 4.463 per 100 kWh, the example home's 185 kWh go from R$ 175.75 to R$ 184.01 (R$ 8.26 more).

6. Why the real bill is different

The bill also has the city's street-lighting fee and the availability charge (a minimum consumption billed even if you use less).
The reading period does not always have 30 days.
Real use changes from month to month: longer showers in winter, air conditioning in summer.

Do the sum

In the electricity cost calculator, type the tariff from your bill and adjust your home's appliances: it shows the cost a month, per day and per year, the kWh and how much each appliance weighs on the bill.

The powers, uses and tariff in this guide are examples to show the sum; use the ones on your appliances' labels and on your electricity bill.

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