Spain · household bill
How to understand a Spanish electricity bill, line by line.
The total is only the end of the story. A useful bill review identifies the contract, measures the energy used, separates fixed power costs and checks every tax, service and solar credit.
Do not begin by hunting for the largest number or the cheapest-looking rate. Start with identity, period and units. A bill can cover an unusual number of days, contain an estimated reading or include a paid service that has little to do with electricity supply.
1. Identify the people and companies
The contract holder is the person or organisation legally responsible for the supply. Check the name, supply address and billing address. The comercializadora is the supplier that sells and bills the electricity. The distribuidora operates the local network, maintains the meter connection and deals with network faults. A household can choose its supplier but normally cannot choose its distributor.
The CUPS is the unique supply-point code. It identifies the connection, not the customer, and is needed for a switch or many contract changes. Treat it as account information: share it only with a trusted supplier or adviser when necessary.
2. Check the bill and meter period
Record the invoice number, issue date, billing start and end dates, and number of days. Compare only bills covering the same period or convert costs to a common annual basis. A 28-day bill and a 35-day bill cannot be compared simply by looking at their totals.
Look for previous and current meter readings and whether each is actual or estimated. An estimated reading can reverse or catch up on a later invoice. If the consumption looks implausible, compare the meter values with the distributor’s customer portal and the physical meter where accessible.
3. Read the energy term
The energy term charges for electricity consumed, measured in kilowatt-hours (kWh). A flat-price contract may show one unit rate. A time-of-use contract can show several periods. An indexed contract may apply a market reference plus a supplier fee or formula rather than one permanent rate.
For each period, copy the kWh, unit price and subtotal. Confirm whether the displayed price already includes regulated components and whether discounts are temporary. Marketing may highlight an energy price while placing the end date or eligibility condition elsewhere.
4. Read the contracted-power term
Contracted power—potencia contratada—is capacity reserved for the home, measured in kW. It is a fixed cost even when consumption is low. Bills can show different contracted levels and prices for peak and off-peak power periods. Record both.
The bill or CNMC bill-understanding tool may also show maximum power demanded. That figure is evidence for a later power review, but one unusually low month is not enough to justify a large reduction. Read the dedicated contracted-power guide before changing it.
5. Separate network charges, taxes and meter costs
Spanish bills include regulated elements that can be presented in different ways depending on the contract and bill design. Check charges connected with network access and policy costs, electricity tax, VAT or IGIC where applicable, and meter-equipment rental if the meter is not owned by the customer.
When comparing suppliers, do not treat a tax change as a supplier discount. Apply the same current tax assumptions to every offer and keep a note of the date. A supplier’s estimated annual bill may include some regulated items while its headline rate does not.
6. Find extra services and contract conditions
Maintenance, emergency assistance, appliance cover, insurance and equipment services can appear as monthly or annual lines. Some are optional; others are tied to a discount. Record the full annual cost and ask whether the tariff is available without the service.
Locate the tariff name, contract end or renewal date, price-review method, minimum-term or permanence condition and any early-exit consequence. The CNMC’s “Entiende tu factura” tool can expose contract type, renewal information, penalties, consumption and demanded power when accessed through the bill’s CNMC QR code or link.
7. For solar, reconcile import and export
A solar bill can show imported energy, eligible exported surplus, the compensation rate and the credit. That is not the same as total solar generation: electricity used directly in the home never passes through the grid import meter, and battery charging adds another flow.
Check that the self-consumption arrangement appears on the contract and that the export period matches the billing period. If compensation is missing, verify registration status, distributor processing and the supplier’s required documents before assuming the meter recorded no export.
A clean comparison record
Copy facts, not marketing language
- Annual consumption
- Sum 12 months of kWh
- Contracted power
- kW in each period
- Paid services
- Annual total in euros
- Solar export
- Measured kWh and credit
These four items create a far better comparison profile than the last bill total alone.
8. Perform a final sense check
- Does the billing period match the meter readings?
- Do the subtotals reproduce the stated total within rounding?
- Are temporary discounts and their end dates visible?
- Are paid services genuinely wanted?
- Does the tariff name match the accepted contract?
- For solar, do export data and compensation cover the same dates?
Official sources
- CNMC — “Entiende tu factura” tool and the information it explains
- CNMC — electricity retail, supply and required bill information
- CNMC energy-offer comparator
Reviewed 28 August 2026. Supplier bill layouts and tax treatment can change; verify the current invoice and contract.