Signing up for electricity and gas with the same company can simplify things, but it does not guarantee the lowest total price. The right comparison puts a dual offer against the annual sum of the best separate contracts for your consumption.
Published by: Reazziona Renovables, S.L., electricity and gas retailer within Grupo Visalia. Last reviewed: 28 July 2026. The method follows the bill components and tools of the CNMC. See the methodology and corrections policy.
What a dual electricity and gas offer means
A dual offer brings both contracts together with the same retailer. It may come with unified customer service, a single customer area and linked discounts. Bills can still be issued separately, because each supply keeps its own CUPS, consumption and regulated items.
When signing up together can pay off
- The discount applies for a meaningful period and does not disappear after a short while.
- The base electricity and gas prices remain competitive once the discount is applied.
- No maintenance plans or insurance you do not need are added.
- Simplifying admin has value for the household and the conditions are clear.
When separate contracts can be cheaper
Separate contracts can be better if one company stands out on electricity and another on gas, if the dual discount is temporary, or if the joint offer requires taking on extra services. It is also worth reviewing them separately when gas consumption is highly seasonal: a high fixed term is paid all year round.
A method for comparing a dual offer
- Work out the annual cost of electricity: energy, power, taxes, meter and services.
- Work out the annual cost of gas: twelve fixed terms, consumption, taxes, meter and services.
- Apply the dual discount for exactly the months stated.
- Repeat the calculation with two separate contracts and the same consumption.
- Compare the second year as well, once the initial promotion has ended.
Questions to ask before you sign
- Does the discount apply to the energy term, the fixed term or the total?
- Until what date are the prices held?
- Is there a lock-in period or penalty on either supply?
- Is a chargeable maintenance service included?
- What price applies when the contract renews?
To review both supplies, see the electricity and gas tariff catalogue, reproduce the calculation with our public methodology and, if you have a bill, use the comparison tool with your real data. Always check the result against the official CNMC comparison tool.