Find the power, in watts
Check the equipment's data plate or manual and write down its power in watts (W). If you have several identical units, multiply by the number. Catalog figures work as a reference; real power and running time can change during use.
CONUEE, Mexico's energy efficiency agency, publishes equipment usage information to help compare options. Use it as guidance and check your exact model: size, temperature, age and operating conditions all change usage.
Source: CONUEE: catalog of equipment and appliance usage ↗Multiply power by time
Convert watts to kilowatts by dividing by 1,000. Then multiply by hours of use and days observed. The result is an estimate of energy in kilowatt-hours (kWh), the same unit shown as usage on your bill.
A hypothetical example: a 1,000 W appliance running two hours a day for 30 days would use about 60 kWh. If a compressor or heating element cycles on and off, don't assume it works all day: measure it or look up the equipment's usage.
Examples of monthly use at home
Estimates for one appliance at the stated use; these aren't averages across all homes.
- Refrigerator33.3 kWh/month400 kWh/year on a sample label ÷ 12
- TV9.6 kWh/month80 W × 4 h/day × 30 days
- Incandescent bulb9 kWh/month60 W × 5 h/day × 30 days
- Wi-Fi router7.2 kWh/month10 W × 24 h/day × 30 days
- Microwave6 kWh/month1,200 W × 10 min/day × 30 days
- Washing machine4.5 kWh/month500 W × 45 min × 12 loads/month
- LED bulb1.35 kWh/month9 W × 5 h/day × 30 days
The bars compare these examples with each other. They assume 30 days; the refrigerator uses a hypothetical yearly label figure divided by twelve.
Three examples, step by step
These are example calculations, not values for every model.
| Appliance | Math | Result in 30 days |
|---|---|---|
| 80 W TV, 4 hours a day | 80 × 4 × 30 ÷ 1,000 | 9.6 kWh |
| 1,200 W microwave, 10 minutes a day | 1,200 × (10 ÷ 60) × 30 ÷ 1,000 | 6 kWh |
| 10 W router, all day | 10 × 24 × 30 ÷ 1,000 | 7.2 kWh |
Don't confuse kW and kWh
Watts (W) and kilowatts (kW) express power: how fast an appliance can use energy at a given moment. Kilowatt-hours (kWh) express energy accumulated over a period. A powerful appliance used briefly can use fewer kWh than a small one that stays on for many hours.
In businesses, maximum demand in kW is different from total energy in kWh. The bill may include items tied to demand and time of day; a simple appliance formula can't rebuild those charges on its own.
Source: Profeco: information on reading the items on your electric bill ↗How to go from kWh to an idea of money
Multiplying by a generic price doesn't reproduce your bill, because the tariff, steps and charges all affect the total. What you can do is estimate what that usage costs based on the step where your bill ends.
For example, with the tariff 1 prices published for October 2026 and 16% IVA (Mexican sales tax): if you end in the excess step, each extra kWh costs about $4.70 pesos, so 33 kWh a month would be close to $155. If you end in the basic step, the same kWh would be about $44. The same appliance costs very different amounts depending on your total usage.
What to look at in the appliances we use most
TV: check the stated power or measure real usage. To compare, screen size and technology matter as much as hours on and brightness. An 80 W TV used four hours a day would use about 9.6 kWh in 30 days; this is a sample calculation, not a value for every model.
Refrigerator: it works in cycles, so multiplying its maximum power by 24 hours usually overstates its use. Look for the yearly usage on the label or data sheet and divide by twelve for a monthly reference; room heat, door openings, seals and settings change the result. Washing machine: use the per-cycle figure if available; if you only have watts, estimate the actual running time and number of loads, knowing the motor's power can vary.
Light bulbs: compare lamps with similar light output, measured in lumens. In the example below, a 60 W incandescent bulb and a 9 W LED run five hours a day. Router: since it stays on, a small power adds up over the whole month. The adapter's label shows its maximum power, which doesn't always match what the device uses; a compatible plug-in meter can measure it.
Source: CONUEE: catalog of equipment and appliance usage ↗How to use the comparison without confusing it with your bill
The chart keeps days of use constant just to make the examples comparable. The refrigerator uses a yearly label assumption; the others use estimated power and time. It doesn't add up a real home's usage or estimate pesos, because the exact model, usage pattern and CFE tariff are missing.
To measure your home, write down the model and label, hours of use or cycles over a week, and repeat in another season if the climate changes. Compare the approximate total with the kWh on your bill: loads you didn't measure, automatic cycles and differences between rated and real power explain why a home estimate doesn't match to the cent.
Source: CONUEE: recommendations on LED bulbs and lighting ↗How to measure better
These options go from simplest to most exact.
- Read the label or data sheet: this works for refrigerators and equipment with a stated yearly usage.
- Use a plug-in meter: it measures appliances that connect to a regular outlet.
- Read your CFE meter: write it down, turn on or off a single piece of equipment for a while and write it down again. This works for large loads.
- Get a professional measurement for fixed loads, such as pumps or air conditioners. Don't open electrical panels yourself.
Sources and scope
The numerical examples are hypothetical. Tariffs and conditions can change and depend on the service; check your bill and current sources before making a decision.
