Electricity consumption calculator: how much each appliance uses

Consultoria EHERO

11 reading minutes

An electricity consumption calculator answers, with three pieces of data, the question we all ask while looking at the bill: how much each appliance really uses. You need the watts it consumes, the hours it is switched on, and the price you pay per kWh. The rest is multiplication.

Below you have the calculator, and after that what almost nobody explains: where the watts come from without making them up. The EU energy label requires each appliance’s consumption to be declared, but not always in watts. The fridge gives it in kWh per year, the TV in kWh per 1,000 hours, and the washing machine in kWh per 100 cycles. Translating those units is the whole trick.

The electricity consumption calculator

Choose an appliance or enter its watts, adjust the hours and the price, and you will see the consumption and cost per day, per month and per year. VAT is calculated separately, because on the bill it appears as its own line.

1. The appliance

A 3.5 kW split unit with SEER 6.1 draws about 574 W on average while cooling.

2. Power and use
3. What you pay

The starting price is indicative: the hourly average of REE’s PVPC between 4 and 17 September 2026 plus the electricity tax. Enter your own if you have it to hand.

Result
Item Per day Per month Per year
Consumption (kWh) — — —
Cost without VAT (€) — — —
VAT 21 % (€) — — —
Total with VAT (€) — — —

A month is 30.4 days (one twelfth of a year) and a year is 365. This is only the energy cost: the bill also includes a fixed charge for contracted power.

The formula, if you want it by hand

It all comes from one calculation: kWh = watts × hours ÷ 1,000. A 1,500 W heater left on for two hours uses 3 kWh. Then, cost = kWh × price per kWh, and VAT is applied on top of that amount.

The other two conversions you need are just as simple:

  • From kWh per year to average watts: divide by 8,760, which is the number of hours in a year. A fridge using 250 kWh per year averages 29 W continuously.
  • From kWh per 1,000 h to watts: nothing needs to be done. The number is the same. A TV using 90 kWh per 1,000 h consumes 90 W.

What number to look at on each appliance

The EU energy label does not use the same unit for everything, which is why so many people end up copying figures from anywhere. This table says what the standard declares for each appliance family and in which regulation it is written.

Appliance What the label declares How to convert it to watts Standard
Fridge and freezer Annual consumption in kWh/year Divide by 8,760 Regulation (EU) 2019/2016
TV and monitor kWh per 1,000 h, in SDR and HDR It is the same number Regulation (EU) 2019/2013
LED bulb and tube kWh per 1,000 h switched on It is the same number Regulation (EU) 2019/2015
Washing machine kWh per 100 cycles of the “eco 40-60” programme Divide by 100 and you have the wash Regulation (EU) 2019/2014
Dishwasher kWh per 100 cycles of the “eco” programme Divide by 100 and you have the wash Regulation (EU) 2019/2017
Electric oven kWh per cycle for each cavity It is already consumption, not power Regulation (EU) 65/2014
Air conditioner kWh per year and the SEER value Cooling capacity ÷ SEER Regulation (EU) 626/2011
Vacuum cleaner Rated power, below 900 W since 2017 It is already watts Regulation (EU) 666/2013
Any standby appliance Maximum 0.50 W off and 2.00 W connected to the mains It is already watts Regulation (EU) 2023/826

For appliances without a label showing declared consumption —microwave, hob, hair dryer, iron, water heater, heater— the data is on the rating plate of the appliance itself, almost always on the back or underneath, next to the voltage. There the number in W is what you need to enter in the calculator, because these are resistive loads that draw their full power while operating.

How much an air conditioner uses

It is the most searched summer question and it has an exact answer in the standard. The air conditioner label declares the SEER, and the average electrical power while cooling is the cooling capacity divided by that SEER. To calculate annual consumption, the regulation assumes 350 hours of cooling per year.

A typical 3.5 kW split unit —what is advertised as 3,000 frigories, which are 3,489 W thermal— works out like this depending on its class:

Class SEER Average power while cooling Annual consumption on the label
A+++ 8.50 412 W 144 kWh
A++ 6.10 574 W 201 kWh
A+ 5.60 625 W 219 kWh
A 5.10 686 W 240 kWh
B 4.60 761 W 266 kWh

With the price used by the calculator, those 201 kWh of an A++ come to about 39 € per year without VAT, 47 € with 21%. Two important caveats: SEER is a seasonal value, so the real power goes up and down depending on how hard the compressor has to work to maintain the temperature, and the 350 hours are a laboratory assumption used to compare equipment. If you use it eight hours a day in July and August, enter your real hours in the calculator.

Washing machine, dishwasher and oven: the cycle rules, not the hour

These appliances do not consume at constant power: they heat water at the beginning and then use almost nothing. That is why the label does not give watts, but energy per cycle, and why the calculator counts washes per month.

The limits for each class come from the regulation’s own formula. For an 8 kg washing machine, the reference consumption of the “eco 40-60” programme is 0.909 kWh per cycle, and the efficiency index sets the maximum for each letter: class A cannot exceed 0.473 kWh per wash and F reaches 0.927 kWh. In other words, double.

For a dishwasher with 13 place settings and more than 50 cm in width, the reference is 1.675 kWh per cycle: class A stays below 0.536 kWh per wash and F below 1.038 kWh. With four washes a week, the difference between one and the other exceeds 100 kWh per year.

The oven is the simplest case: the label gives the kWh per cycle for each cavity, measured with a standardised load. A cycle is not an hour of oven use, but the full test defined by the standard, so use it as a reference to compare models, not as a stopwatch.

The default kWh price

The calculator starts from 0.1944 €/kWh without VAT. It is not a tariff or a recommendation: it is a starting point built from public data and should be replaced with your own.

It comes from two places. First, the active energy billing term of the PVPC published by Red Eléctrica in e·sios: between 4 and 17 September 2026 its hourly average was 184.93 €/MWh, that is 0.1849 €/kWh. On top of that goes the Special Electricity Tax, 5.11269632%, set by Law 38/1992, and that is where the 0.1944 comes from.

Two warnings. One: PVPC is hourly and moves a lot. In those fourteen days there were hours at −10.70 €/MWh and hours at 431.34 €/MWh, so an average is just that, an average. Two: this price is only for energy. The bill also includes the fixed contracted power charge, which is paid even if you switch nothing on, and that is why the calculator’s result will never match your bill total exactly.

Electricity VAT is separate

On the electricity bill, VAT is applied at the end, on the sum of energy, power and electricity tax. The rate that applies today is the general 21%: Article 90 of Law 37/1992 sets it as the general rate, and Article 91, which lists what goes at 10%, does not include electricity supply.

It is worth saying because the European Commission’s VAT rates database still shows 10% for Spain in the sustainable energy category, a legacy of temporary cuts from previous years. When a European database and national law do not match, national law prevails. That is why the calculator comes with 21%, and lets you choose 10% or 0% in case you are checking an older period or a different country. Country-by-country rates are in our table of EU country VAT rates in 2026, and the Spanish detail is in the VAT in Spain sheet.

Do you sell appliances or electrical equipment in WooCommerce?

If you ship to other EU countries, each order carries the customer’s country VAT and not all countries treat energy and appliances the same. EHERO Woo VAT applies the destination rate according to the product tax class, respects the custom classes you create for items whose rate changes between countries, watches the 10,000 € threshold, and validates the VAT number in VIES during checkout.

See EHERO Woo VAT →

Frequently asked questions

How much does an air conditioner use per hour?

Average power is the cooling capacity divided by the SEER on the label. A 3.5 kW A++ split unit (SEER 6.10) uses about 0.57 kWh per hour; the same unit in class B, about 0.76 kWh. Instantaneous consumption varies: it draws more when starting up and then drops.

How much does a fridge use?

Its label says so in kWh per year. Divide that figure by 8,760 and you get the average watts: a fridge using 250 kWh per year is equivalent to 29 W continuously. There is no need to estimate hours, because it is plugged in all year.

How do I know the watts of an appliance that does not have an energy label?

On the rating plate, the sticker or plate with the voltage and model. On microwaves, irons, hair dryers, heaters or hobs, that number in W is directly what they consume while operating.

How much does an appliance use in standby?

Very little, and it is also limited by law: at most 0.50 W in off mode and 2.00 W in standby connected to the mains. An appliance connected to the mains all year is about 18 kWh, a little over 4 € with VAT at the price on this page.

Why does the result not match my bill?

Because the calculator only measures energy. Your bill also adds the fixed charge for contracted power, the electricity tax, the meter rental and, at the very end, VAT. Also, the kWh price changes every hour if you have PVPC.

Sources

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