At a time when energy prices are unstable and home spending increasingly weighs on the family budget, knowing how to calculate electrical consumption in KWh can be a simple but very useful step in reducing expenses and adopting more efficient habits. Although it may seem complicated, this calculation is easy to do and is available to anyone. Understanding how it works can help a lot when the light account comes at the end of the month.
What does KWh mean?
A kWh (kilowatt-hour) is the energy measure consumed by a power device of 1,000 watts for one hour. For example, a 1,000 W heater on for an hour consumes exactly 1 kWh. This is the amount that appears in the invoice and, multiplied by the price of electricity, determines what you have to pay.
How to calculate electrical consumption?
To know the consumption of each home appliance, just follow three simple steps:
- Check the power of the device (in watts), normally indicated on the label or manual.
- Multiply this power by the number of hours of use per day.
- Divide the total by 1,000 to get consumption in kWh.
The formula is: Daily consumption (kWh) = (power (w) × use time (h)) ÷ 1,000
To calculate monthly consumption, the result is multiplied by the number of days the device is used.
Practical Example:
A 150W power fridge, on 24 hours a day:
(150 × 24) ÷ 1,000 = 3.6 kWh Por he
3.6 × 30 = 108 kWh per month
Price per kWh depends on the supplier
The value of kWh varies between companies. According to April 2025 data, Galp had the lowest price (0.1456 €/kWh), while others like Repsol or EDP had slightly higher values. This cost, multiplied by monthly consumption, determines the main value of the invoice – to which other charges are added, such as fees and taxes.
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Where to consult your costs?
In your light account, usually on the second page, you can see:
- Total kWh consumed
- Unit price for kWh
- Additional charges (hired power, fees, VAT, among others)
For example, 200 kWh consumed in a month with a price of 0.15 €/kWh, the cost of energy consumed was 30 €. The remaining charges are added to this value.
How to save energy and money?
Knowing how to calculate consumption is just the first step. Here are five practical suggestions to reduce the monthly invoice:
- Evite o modo standby: Turn off the plugs from the outlet or use extensions with switch.
- Change LED lamps: They consume less and last longer.
- Opt for Class A Appliances: They are more efficient.
- Enjoy the natural light: Keep curtains open during the day.
- Avoid heat losses: Isole well windows and doors not to use so much heating or air conditioning.
Comparing suppliers makes a difference
“Prices are always changing and depend on their consumption and profile. The best way to make sure it makes the right choice is to compare,” recommends the comparison.pt. Online tools can help find the most appropriate fare.
Mastering this type of calculation and being aware of available offers can have a direct impact on family budget management.
In times of uncertainty, each small savings makes the difference – both for the wallet and the environment
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