Single-rate or two-rate (bi-horária) tariff: which pays off?
The two-rate tariff pays off from 38% of usage in off-peak hours. You are at 35%.
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Your prices (€/kWh)
How we calculated it
It compares the energy cost on both tariffs with your usage. The starting prices are examples: use the ones on your bill or on the offer you received.
It does not include the fixed power charge, which is usually the same on both. Check your off-peak hours on your bill.
Example: you use 300 kWh a month and half of it is off-peak (vazio). With the calculator's starting prices, the two-rate tariff saves about €45 a year compared with the single rate. With the same 300 kWh and only 30% off-peak, the single rate is cheaper, by about €31 a year. At these prices, the two-rate tariff pays off from 38% of usage off-peak.
Frequently asked questions
When is off-peak (vazio) on a two-rate tariff?
Mainly at night. The exact hours depend on the cycle, daily or weekly, shown on your bill.
Does the two-rate tariff always pay off?
No. It only pays if you use a good share of your energy off-peak; the calculator tells you from what percentage.
What are the off-peak hours on the daily cycle?
On the daily cycle, off-peak runs from 22:00 to 08:00, every day. ERSE (the energy regulator) has approved a change to 22:30 to 08:30, which homes will switch to between July and December 2027.
What is the VAT (IVA) rate on electricity?
On the mainland, with contracted power up to 6.9 kVA, the first 200 kWh of every 30 days pay 6% VAT, or 300 kWh for large families. The rest of your usage pays 23%.
What is the three-rate (tri-horária) tariff?
It is a tariff with three prices: off-peak (vazio), mid-peak (cheias) and peak (ponta). Peak is the most expensive period and off-peak the cheapest. This calculator only compares the single rate with the two-rate tariff.