A guide to reading your Spanish electricity bill. Updated 21 September 2026.
Start with two numbers: the energy you use in kWh and the power you contract in kW. They measure different things and appear as separate charges. Understanding that difference helps you decide whether changing the time you use electricity can reduce your cost.
This is the consumption part of the bill. Look for kWh and a price per kWh. For a simple constant-rate example, 100 kWh at €0.20/kWh costs €20 for energy. Keep the tax basis consistent when comparing a supplier quote with a bill.
This relates to the power capacity contracted for your home, measured in kW. It is separate from the energy you consume. Moving a washing cycle to another hour does not by itself change your contracted power.
Your total may also include taxes, meter rental, and services you have contracted. Check each line before comparing offers. The CNMC’s electricity guide explains these components.
A hypothetical appliance drawing a constant 1 kW for two hours uses 2 kWh. At a hypothetical €0.20/kWh energy rate, that is €0.40. Real appliances often vary their power during a cycle, so their rated maximum power is not necessarily their average consumption.
Look for PVPC in the contract details on your bill. Red Eléctrica publishes the hourly regulated energy prices. Power Window uses that series to help you compare when to run a flexible load. See Red Eléctrica’s PVPC explanation.
If your contract has one fixed unit price all day, shifting the same kWh to another hour does not lower that energy charge. With a time-of-use offer, use your supplier’s period prices. To identify your plan, follow the bill’s CNMC link or QR code to Entiende tu factura.
Imagine a flexible load that uses 2 kWh. At a hypothetical constant €0.30/kWh it costs €0.60; at €0.15/kWh it costs €0.30. The difference is €0.30 for that use. These invented rates illustrate the calculation; they are not today’s prices or a saving forecast.
If the load spans several hourly prices, multiply the energy used in each hour by that hour’s rate and add the results. Starting at the cheapest hour is not enough when the next hours are expensive. The planner compares continuous windows using your selected duration and approximate power.
Record the planned time, actual duration, and available consumption reading. Compare the energy estimate on the same basis as your tariff. Keep the rest of the bill separate: a lower cost for one wash does not mean every bill item falls by the same percentage.
For laundry, read the washing-machine guide. For a longer load, use the EV charging guide. For contract comparisons, enter the actual offer in the tariff comparator and review the calculation assumptions.