You go away for a week, barely switch a light on, and the bill comes back almost unchanged. Or you pay roughly the same amount for several months and then get one that is twice the size. In Portugal both can be normal: part of a utility bill has nothing to do with how much you use, and instead of a meter reading your supplier sometimes works from an estimate and settles the difference later. So to understand where the number came from, don’t just compare the bill with last month’s. Check four things first: how many days the bill covers, whether the readings are real ones, how much of the total is fixed charges, and whether there is a correction for earlier months.
Electricity: what you pay for even when you are not using it
An electricity bill has two main parts. The first depends on how many kilowatt-hours you used. The second depends on potência contratada — the amount of power available to the flat at any one moment. On top of those come network access charges, taxes and mandatory levies. Your supplier has to show every one of these separately; the full list is in ERSE’s guide to reading a bill.
Think of potência contratada as a ceiling on load. Switch on the oven, the water heater, the washing machine and a heater at the same time and too low a ceiling won’t hold — the power trips. But the higher the ceiling, the larger the fixed part of the bill, including in an empty flat.
If the power never trips, even with several heavy appliances running at once, you may be paying for headroom you don’t need. You can check the right level in ERSE’s power simulator, and change it through your supplier.
How a time-of-day tariff works
On the tarifa simples, the simple tariff, a kilowatt-hour costs the same all day. Bi-horária is the two-period tariff: the day is split into expensive and cheap hours. Tri-horária, the three-period tariff, has three such periods. A two-period tariff makes sense if you genuinely move laundry, the dishwasher, water heating or car charging into the cheap hours. If most of your consumption falls in the expensive period, it can work out worse.
Changing tariff is free. For the two- and three-period tariffs you also choose the schedule of cheap and expensive hours. On the daily cycle it is the same on every day of the week; on the weekly cycle it differs on weekdays, Saturdays and Sundays. That is not a separate tariff, only a way of spreading its price periods across the week. The cycle you choose normally stays in place for at least a year. ERSE publishes the detailed rules.
Why the electricity bill suddenly went up
Compare two months not by the total but by the kilowatt-hours and the number of days. If the kilowatt-hours went up, the reason is usually domestic: a heater or a dehumidifier switched on for the winter, the water heater running longer, an old fridge drawing more than it used to.
If consumption barely moved, check whether:
- a discount ran out or the tariff changed;
- a paid service or an insurance policy appeared;
- potência contratada went up;
- the bill covers a longer period than usual;
- the readings are marked as real or as estimated;
- there is an acerto line — a correction for previous months.
You can load your own contract into ERSE’s official price simulator and compare it against current offers. That is more useful than looking at the advertised price per kilowatt-hour: the simulator takes your power level and tariff scheme into account.
Estimativa and acerto: why one bill can cover several months
A high bill after several quiet months doesn’t necessarily mean you spent that much now. The earlier estimates may have been too low, and the supplier has now billed the accumulated difference. Look for the words real and estimado or estimativa next to the readings. The second means the company didn’t receive meter data and worked your consumption out approximately. When real readings arrive, they are compared with what has already been charged, and the difference lands on the next bill as an acerto.
A smart meter usually sends its data by itself, but a digital display doesn’t guarantee that the remote connection is working. In Balcão Digital E-REDES you can see whether the operator is receiving your readings and what data it passes on to your supplier.
If there is no automatic transmission, you can submit readings through the E-REDES account or app, by freephone, or through your supplier. The right date is usually printed on the bill.
If the correction comes to at least as much as your average monthly charge over the previous six months, the supplier has to attach a payment plan to the bill — up to 12 instalments, with no more than a quarter of average monthly consumption in any one bill. You can still pay the whole thing at once if you prefer.
Gas: why the meter shows cubic metres and the bill shows kilowatt-hours
A natural gas meter measures volume in cubic metres, but you are charged in kilowatt-hours. That is why the bill carries a conversion factor: the supplier has to show it and explain the calculation. Besides the gas itself, the total includes a fixed part, network access, taxes and any add-on services.
Natural gas also has an escalão de consumo — a consumption band that depends on how much you use in a year. After the first year the operator checks whether the band matches your actual consumption, and then repeats that check annually. The band thresholds and how they are changed are explained by ERSE.
If you use gas only for the hob and hot water and consumption has jumped sharply, compare the readings and check the equipment. A correction can appear after estimated readings, a misread meter or a faulty one. If the adjustment is in the supplier’s favour, you can ask to pay it in instalments, taking into account the number of months the difference built up over.
Gas bottles are not part of a utility bill: you buy them separately. If the building is supplied with liquefied gas from a shared tank, how you pay for it is set out in the lease and in the bills from that particular supplier.
Water: why sewerage and waste collection come with it
You don’t choose your water supplier: water is the responsibility of the local or municipal company. That is why tariffs, and even the names of the lines on the bill, differ from city to city.
The bill usually covers not only water but a fixed network access charge, sewerage, wastewater treatment, waste collection and a levy on the use of water resources. In Lisbon, for example, EPAL collects the municipality’s sewerage and waste charges at the same time as its own. Those services have a fixed part and a variable part calculated from the cubic metres of water. So when water consumption rises, several lines rise together.
Water itself is usually charged in bands: the next cubic metres can cost more than the previous ones. So start by checking what period the bill covers. If two months went into it, the total will naturally be higher than a monthly one — compare average monthly consumption, not the amount due.
If the number of cubic metres has gone up with no obvious explanation, turn off every tap, leave the appliances switched off, and look at the meter. If it is still moving, you probably have a leak. A running toilet cistern, a faulty water heater or a pipe are the usual culprits.
Whose name the contract should be in when you rent
If the owner is going to be responsible for the payments, the lease has to say precisely who pays for the meters and the utilities, and when. The tenant will also need copies of the bills.
To open a new electricity or gas contract, or to transfer an existing one into the tenant’s name, you are normally asked for a passport or another identity document, a NIF, the lease, the CPE for electricity or the CUI for gas, and current readings. The CPE and CUI are printed on old bills. On the day you move in, photograph the meters so that both the figures and the serial numbers are visible: that separates your consumption from the previous tenant’s.
For water, the list of documents is set by the local operator. In Lisbon, EPAL asks for identification, proof of your right to occupy the flat and the owner’s details; opening the contract is free. In Porto, a transfer also requires current meter readings and proof of your right to use the property.
What to do if the bill looks wrong
Start by checking the address, the customer name, the meter number, the CPE or CUI and the billing period. Then compare the readings on the bill with the figures on the meter, and check whether they are real or estimated. After that, separate actual consumption from the fixed charges and find any acerto, estimativa or correção lines.
If there is still no explanation, write to the supplier and attach a photograph of the meter, the bill in question and several earlier ones. Don’t ask them to “check the amount” in general — ask them to explain the specific discrepancy: why the closing reading on the bill doesn’t match the meter, for instance, or what period the correction covers.
Don’t simply cancel the direct debit and forget about the bill. If a complaint about electricity sets out specific signs of an error, the supplier cannot cut off your electricity over the unpaid disputed bill until it has replied to you. This rule comes from ERSE.
If the supplier hasn’t corrected the error, you can file a complaint through the electronic Livro de Reclamações. ERSE handles electricity and gas; ERSAR handles water and waste. Keep the reference number, the photographs and the replies: if the dispute has to go further, that is your timeline of events.
