How to calculate a home's electricity consumption Practical guide with examples and tips

What electricity consumption is and how it is measured

To calculate your electricity consumption, you need to know the power rating of the devices you use and how long you use them. Your bill is calculated based on the total energy used during the billing period.

This means you must know the power rating of your appliances and lighting, and factor in the time you have them switched on. You should also be aware of your actual consumption and the current price of electricity. Combining this with an understanding of your habits and being able to adjust them allows you to improve energy efficiency, choose the Endesa plan that best suits your routine, and save on your bill.

Thanks to smart meters, you can now find out your consumption instantly. In addition, they offer advantages such as:

• Actual consumption reading on the bill.
• Ability to check consumption anywhere and at any time via a device.
• Reliable measurement.

Factors that influence household electricity consumption

Energy usage doesn't depend solely on the number of appliances you have at home, or how you use them. Consumption varies greatly from one home to another depending on several factors such as:

• Household size: the more people living in a house, the more time is spent cooking and the more laundry is done, fridges have a larger capacity (generally), and homes are also larger, requiring more energy for heating and cooling.
• Characteristics of the property: well-insulated spaces need less energy to maintain a correct temperature. Orientation and windows maximise natural light, which reduces the need for electric lighting.
• Lifestyle: how you live is a significant factor when determining annual electricity consumption. Maximising efficiency lets you actively reduce energy consumption; options range from controlling the use of devices and avoiding standby mode, to choosing efficient appliances and low-consumption programmes.

How to calculate your home's electricity consumption step by step

Calculating your electricity consumption isn't complicated if you follow a methodical process. Here's how:

Check the total consumption on your electricity bill

On your bill you will find a section indicating the total consumption for the billing period in kWh, normally under the heading 'Energy consumption' or 'Consumption details'. This figure reflects the sum of the usage of all electrical equipment during the month.

For example, if in a month the final amount on your bill is 250 kWh, then that's the total energy consumption in the home during that period. You can also check your consumption history on the retailer's website or app.

Calculate the consumption of each appliance

To estimate individual appliance usage, find the appliance's power rating (in W) and convert it to kW (divide it by 1,000). Then multiply the result by the hours of use per day and by the days of the month.

For example, this is the calculation for a 0.1 kW TV used 4 hours a day: 0.1 kW × 4 h × 30 days = 12 kWh/month.

To estimate your total appliance consumption, add up the monthly consumption of all devices, then multiply that number by the price per kWh of your tariff (for example, €0.15/kWh) to determine the cost.

Knowing how much your appliances consume is incredibly useful, which is why we have drawn up a list of the most common appliances and bulbs, accompanied by their typical power ranges:

• TV: 100–400 W (0.1–0.4 kW).
• Air conditioning: 900–2,000 W (0.9–2 kW).
• Microwave: 900–1,500 W (0.9–1.5 kW).
• Fridge: 200–400 W (0.2–0.4 kW).
• Oven: 1,200–3,000 W (1.2–3 kW).
• Incandescent bulb: 30–80 W (0.03–0.08 kW).
• LED bulb: 3–12 W (0.003–0.012 kW).

Analyse consumption and estimate the cost

To find the consumption, multiply this power in kW by the hours you have these devices switched on in a day, a week or in a month.

Let’s look at a practical example using Inés and Román's home:

Their TV has a power of 200 W, i.e. 0.2 kW. They have it on for 2 hours a day, meaning their daily consumption is 0.4 kWh. To find their monthly consumption, simply multiply their daily consumption by the number of days in the month, for example, 30. This gives a monthly consumption of 12 kWh.

If you do this for all the electrical appliances in Inés and Román's house, you can determine their exact consumption.

This information is very useful, not only to gain control over the use of appliances and achieve efficient use, but in helping to choose the right appliances. Remember that all devices must be accompanied by their corresponding efficiency information, in addition to their technical specifications where their power rating must be indicated.

Tools to calculate and control your consumption

There are several online calculators and apps to help you check your appliances' energy demand and how much you consume per month.

At Endesa we have an energy consumption simulator, where you can enter the data for your appliances and the hours of use. Also, the applications and websites of the energy companies allow you to see your hourly consumption and compare it with previous months.

Web calculators like Tarifa Luz Hora allow you to enter data on power, hours of use and contracted tariff, enabling you to calculate your monthly consumption. In addition, there are smart plugs or measuring devices that connect to sockets and show the exact consumption of each appliance.

What does kWh mean on the bill?

The term kWh (kilowatt hour) represents the amount of energy consumed when using 1,000 watts for one hour. It is the unit that determines the variable cost of your bill. Each energy company applies a price per kWh, which may vary according to the tariff and the time slot.

On your electricity bill, 'energy consumed' section shows the kWh you have used. The final price depends on the quantity of kWh multiplied by the cost of the tariff you have contracted. (If you consume 300 kWh, and your tariff is €0.15/kWh, you will pay €45)

How to check your home's monthly kWh usage

You can find out your monthly consumption by checking your electricity bill, where the energy used during the billed period is indicated. Alternatively, access your retailer's 'Customer Area', which usually shows images, tables and charts detailing your consumption by hours, days and months.

If you have a smart meter, then you can check your consumption in real time. This is a very useful option, ideal for identifying if peaks have occurred or there are energy leaks.

Average electricity consumption of a home in Spain

According to Spain's Institute for Energy Diversification and Saving (IDAE), the average annual consumption per household in Spain is around 3,500 kWh (between 270 and 300 kWh per month), although it varies according to the type of home and climate zone.

Single-family houses with electric heating can easily exceed 5,000 kWh per year, while small flats without this type of system can consume less than 2,500 kWh. These figures are just a snapshot of electricity consumption in Spanish households: of the total electrical energy consumption, heating accounts for 7.4% and air conditioning for 7.5%.

Kitchen appliances account for 9.3% of consumption, while fridges and freezers account for 2.3%. Household lighting makes up 11.7% of consumption, while the rest of the appliances make up 55.2%. Finally, devices on standby mode account for 6.6% of usage.

What about individual devices? Fridges consume 30.6%, while freezers represent 6.1%. Washing machines account for 11.8%, while dishwashers account for 6.1% and clothes dryers 3.3%. Ovens account for 8.3% of usage. Screens such as the TV contribute 12.2%, and computers 7.4%. Standby mode makes up 10.7% of demand, and other appliances account for 3.5%.

Appliances that consume the most

Excluding heating and air conditioning, these are the four appliances that consume the most in your home:

1. Fridge

According to the IDAE, 99.6% of Spanish households have a fridge. As we've seen, its consumption can account for 30.6% of total energy, since it runs 24/7. Keep in mind that when the temperature is low, the fridge does not operate at full capacity and does not use maximum power. Likewise, the higher its efficiency labelling, the lower the consumption. A fridge consumes about 655 kWh per year, according to IDAE estimates.

2. TV

According to Statista, 98.6% of Spanish households have a TV. Its consumption is 12.2% of the total. If we spend an average of 228 minutes a day watching television, this amounts to 1,387 hours of television per year. A single TV at home uses approximately 119 kWh annually, estimates IDAE.

3. Washing machine

The washing machine makes up 11.8% of total electricity consumption in Spanish households, and is found in 92.9% of households. Again, appliance efficiency plays a key role in reducing consumption levels. Washing in cold water or using saving programmes significantly reduces usage. According to IDAE, a washing machine consumes about 254 kWh per year.

4. Oven

The National Statistics Institute (INE) points out that 88.3% of Spanish households have an oven. Ovens account for 8.3% of electricity consumption according to the IDAE. The type of oven, responsible use and its energy efficiency label determine its level of consumption, as well as the number of hours it is kept on. An oven uses an estimated 1.5 kWh for every hour it is switched on. If you use an oven for a couple of hours a week, consumption comes to about 150 kWh per year.

Appliance consumption table

Below is a table showing the estimated annual consumption of the main electrical devices in your home, with data obtained from the official report of the Ministry for the Ecological Transition and the Demographic Challenge (MITERD) on residential energy consumption in Spain for 2025.