What your energy certificate (certificado de eficiencia energética) really tells you

Key rules

• Mandatory: You can expect the owner to provide an energy certificate for any sale or rental, unless the home is exempt.
• Validity: The certificate lasts 10 years, and the A to G letter must be shown in sale and rental adverts.
• Reliability: The letter is a standard calculation, so treat it as a rough guide and not a bill forecast.
• Registration: A valid certificate carries a registration number from the regional register.

The short answer

Every home sold or rented in Spain needs an energy certificate (certificado de eficiencia energética), with a few exceptions. The owner must give it to you. The A to G letter is a useful guide to the building, but it is a standardised calculation. It only partly predicts how comfortable the home will be or what your bills will be.

When the certificate is mandatory

The owner must have a certificate before selling or renting, and must hand a copy to the buyer or tenant. The letter must also appear in sale and rental adverts. Ask for the certificate before you commit to anything.

The certificate is valid for 10 years. If it has expired, the owner must renew it before selling or renting. An owner may also update it earlier after reforms that change the rating.

Some homes are exempt:

• Protected historic buildings and places of worship.
• Temporary buildings, meaning those in use for under two years.
• Small buildings under 50 m² of useful area.
• Buildings used fewer than four months a year, and rentals of less than four months a year.
• Some industrial or agricultural uses.

Who issues it and what to check

A qualified technician draws it up: an architect, technical architect, engineer or technical engineer, or another professional competent to design or certify buildings. The technician usually visits the home and calculates the rating with official software. The certificate is then registered with the energy register of the region where the property is. That register issues a registration number.

Check that the certificate shows this number and has not expired. Fines for selling or renting without one are set by regional rules and national consumer law, so the amount depends on the region.

What the letter does and does not tell you

The letter is a fair relative guide to insulation, windows and heating systems. On average, better-rated homes cost less to run. For any single home, though, it is a weak predictor.

• It is a model, not a measurement. Many ratings use simplified default values, for example for wall and roof insulation, because the technician has no building plans.
• Your habits matter. Bills depend on the climate zone, how many rooms you heat and whether you heat at all.
• Poorly rated homes can cost less than the label suggests. Occupants often ration heating and accept low comfort.
• Efficient homes can cost more than the label suggests. People tend to heat them more.

What to do at a viewing

• Ask to see real energy bills for the last year.
• Look at orientation, damp and the type of heating yourself.
• Use the letter to compare homes, not to forecast your bills.

The timeline, documents, checklist and questions below cover the practical steps.

Timeline and deadlines

• Hire a qualified technician to assess the home: before you advertise, sell or rent

• The technician visits and calculates the rating with official software: usually after a site visit

• The technician registers the certificate with the regional register: once the rating is calculated

• Show the A to G letter in every sale or rental advert: from the day you advertise

• Give the certificate to the buyer or tenant: when the sale or rental goes ahead

• Renew the certificate if it has expired, or update it after reforms that change the rating: before expiry if you want to sell or rent; the validity period is set out in the main article

Documents you need

• Energy efficiency certificate (certificado de eficiencia energética), drawn up by a qualified technician such as an architect or engineer. The owner must provide it to the buyer or tenant when the home is sold or rented.

• Proof of registration with the regional register of the region where the property is, showing the registration number the register issues. A certificate that is not registered is not complete.

Checklist

• Ask the owner or agent for the energy certificate before you commit to a sale or rental.

• Check that the advert shows the energy letter from A to G.

• Check that the certificate carries a regional registration number and has not expired.

• Find out whether the home is exempt, for example under 50 m² or used fewer than four months a year.

What to watch out for

• Selling or renting without a certificate: A seller or landlord who has no certificate, or does not show the letter in the advert, can be fined. Penalties are set by regional rules and national consumer law. If you are the seller or landlord, order the certificate before you advertise. If you are the buyer or tenant, ask for it before you sign.

• Treating the letter as a bill forecast: The rating comes from a standardised model, not from measuring the home. Many are built on default values because the technician lacks building plans, so the letter can mislead for one particular home. Compare the letter with real bills, orientation, damp and heating type before you decide.

Frequently asked questions

Does an A rating mean my energy bills will be low?

Not necessarily, because an A rating is a calculated score and not a measurement of what you will pay. Bills also depend on climate zone, how many rooms you heat and how you live. On average, better-rated homes do cost less to run, so ask the owner for real bills as well.

Why can a poorly rated home cost less than its label suggests?

Occupants of poorly rated homes often ration heating and accept lower comfort, so they use less energy than the calculation predicts. The opposite happens in efficient homes, where people often use more than predicted. Treat the letter as a guide to insulation, windows and heating, not as a bill forecast.

Is an energy certificate needed for a home under 50 m²?

No, buildings under 50 m² of useful area are exempt from the energy certificate. Protected historic buildings, temporary buildings under two years and homes used fewer than four months a year are also exempt. Ask your region's energy office if your case is borderline.

Who is allowed to draw up the energy certificate?

A technician with a qualifying degree, such as an architect or an engineer, draws it up. They usually visit the property and use official software to calculate the rating. The certificate is then registered with the regional register, which issues its registration number.