Who pays for the energy certificate, the buyer or the seller?

The seller pays. The obligation to hold a certificate belongs to the property owner and exists before the property is advertised. The buyer hires nobody and pays nothing, and should receive the certificate at no cost. If you are asked to pay for the certificate of the home you are buying, someone is passing you an obligation that is not yours.

Can I buy a house that has no energy certificate?

You should not proceed with the matter unresolved. The certificate is mandatory for the sale and the seller must have one. If it does not yet exist when the promissory contract is signed, insist that the CPCV sets a delivery deadline before the deed and the consequences of missing it. A verbal promise leaves you with no argument on the day.

Is a house with an F energy class a bad buy?

Not necessarily. An F class says the building consumes a lot for the comfort it delivers, which is common in older uninsulated construction. If the price already reflects that and the improvement measures listed in the certificate fit your budget, it can be a good buy. The mistake is paying an efficient-home price for a home that will need work.

Does the energy certificate expire?

Yes. It has a validity period and the expiry date is printed on the document itself. Check it first: an expired certificate is no good for a sale and must be reissued by a qualified assessor. Validity is not the same for every type of building, so the date on the document is the only reliable answer for that property.

Can the energy class improve after renovation works?

It can. Replacing windows, insulating the roof or changing the hot water system alters the calculation. For the new class to be on record, a fresh certificate must be issued by a qualified assessor once the works are finished. If you plan to sell or let later, or to apply for grants or credit with terms tied to energy performance, updating it is worth doing.

The buyer's guide

Energy certificate: when it is required and what the classes mean

An energy certificate is mandatory whenever a property is sold or let, and the obligation falls on the seller. It must exist before the property is advertised, the class must appear in the listing, and the certificate is handed to the buyer by the time of the deed. The class, from A+ to F, does not measure your future energy bill: it measures the building's theoretical performance, calculated from insulation, windows, orientation and installed equipment. For a buyer, the document's value is not in the letter. It is in the list of improvement measures inside it, because that is the likely budget for the work you will end up doing.

When it is required, and whose obligation it is

It is required at three moments: to advertise, to sell and to let. The certificate must be issued before the property goes to market, and the energy class must appear in the listing, portals included. A listing with no class shown means either the certificate does not exist yet or nobody has dealt with it.\n\nThe obligation belongs to the owner, not the buyer. The owner hires the qualified assessor and pays for issuance. In practice the selling agency almost always handles it, because without a certificate it cannot legally advertise. A new building also needs one on the path to its licença de utilização.\n\nThe regime comes from Decreto-Lei 101-D/2020, which created the Sistema de Certificação Energética dos Edifícios, since revised by later legislation. ADENE runs the system, and certificates are issued by registered qualified assessors. The law does provide exemptions, but they are few and specific. If you are told a property is exempt, ask to be shown the basis for it.

What the class measures, and what it does not

The class is not your bill. It is the result of a calculation: the assessor estimates the property's energy needs for heating, cooling and domestic hot water, and compares them with a reference building. That calculation takes in wall and roof insulation, glazing and window frames, solar orientation, floor area and installed equipment such as a boiler, a water heater, a heat pump or solar panels.\n\nWhat it does not take in is how you will live there. Two identical flats, one occupied by someone who is out all day and the other by a family with small children, carry the same class and very different bills. So the class is a tool for comparing properties with each other, not for predicting your monthly cost.\n\nIt also does something more useful: it tells you where the building is weak. A low class is rarely a mystery. It is usually single glazing, no insulation in older construction, or electric water heating with no alternative.

The scale runs from A+ to F, with one step almost nobody knows

The Portuguese scale runs from A+, the best performance, down to F, the worst, and includes a little-known intermediate step: A+, A, B, B-, C, D, E, F. B- is a class in its own right, not a variant of B.\n\nA high class means the building needs little energy to stay comfortable. A low class means the opposite, and translates into two concrete things: higher bills and less thermal comfort. Much of the housing stock built before thermal insulation requirements sits in the lower half of the scale, and that does not make it a bad buy. What makes it a bad buy is purchasing without budgeting for the fix.\n\nNew construction is subject to a minimum class set by regulation. If you are buying off-plan or recently built and the class looks low for the year of construction, ask why before you sign anything.

How to read the certificate before you buy

Ask for the full document, not a screenshot of the listing. Check the identification first: address, unit, floor area and certificate number must match the property you are viewing and the caderneta predial. A certificate issued for the flat next door is worthless.\n\nThen go to the part that matters to a buyer: the improvement measures. The certificate lists recommended works, with the expected gain and an estimate of cost and payback. It is, in effect, a preliminary works budget drawn up by a technician who was inside the property. New window frames, roof insulation, a replacement hot water system: add those figures up and set them beside the asking price. The maths changes.\n\nAlso check the issue date and the expiry date, both printed on the certificate. An expired certificate is the same as no certificate.

Where the class costs or saves you money

Three fronts. The first is the most obvious and the most certain: running cost. A poorly insulated home costs more to heat every winter you live there, and that cost appears nowhere in the deed.\n\nThe second is tax. There is a possible IMI reduction for buildings with high energy performance, but it depends on a decision by the municipality where the property sits, and carries its own conditions and deadlines. Do not assume it applies to you. Check with the câmara municipal and the Portal das Finanças before counting on it.\n\nThe third is financing. Several banks run mortgage products with specific terms for properties with a high energy class. Those terms vary between banks and change often, so ask yours directly, with the property's class in hand. If you are comparing offers, it is one more variable for the table.

How to confirm the certificate is real and still valid

Every certificate carries a number in the Sistema de Certificação Energética and names the qualified assessor responsible for it. The system has a public lookup: with the number you can confirm the certificate exists, which property it belongs to and how long it remains valid. Do that check before the CPCV, not after.\n\nIf the seller has no certificate, that is the seller's problem and no reason for the buyer to soften the requirement. Issuance does not depend on you. What must not happen is arriving at the deed with the matter unresolved, or accepting a verbal assurance that it will come through in time without the deadline being written into the promissory contract.

Common questions

Who pays for the energy certificate, the buyer or the seller?: The seller pays. The obligation to hold a certificate belongs to the property owner and exists before the property is advertised. The buyer hires nobody and pays nothing, and should receive the certificate at no cost. If you are asked to pay for the certificate of the home you are buying, someone is passing you an obligation that is not yours.
Can I buy a house that has no energy certificate?: You should not proceed with the matter unresolved. The certificate is mandatory for the sale and the seller must have one. If it does not yet exist when the promissory contract is signed, insist that the CPCV sets a delivery deadline before the deed and the consequences of missing it. A verbal promise leaves you with no argument on the day.
Is a house with an F energy class a bad buy?: Not necessarily. An F class says the building consumes a lot for the comfort it delivers, which is common in older uninsulated construction. If the price already reflects that and the improvement measures listed in the certificate fit your budget, it can be a good buy. The mistake is paying an efficient-home price for a home that will need work.
Does the energy certificate expire?: Yes. It has a validity period and the expiry date is printed on the document itself. Check it first: an expired certificate is no good for a sale and must be reissued by a qualified assessor. Validity is not the same for every type of building, so the date on the document is the only reliable answer for that property.
Can the energy class improve after renovation works?: It can. Replacing windows, insulating the roof or changing the hot water system alters the calculation. For the new class to be on record, a fresh certificate must be issued by a qualified assessor once the works are finished. If you plan to sell or let later, or to apply for grants or credit with terms tied to energy performance, updating it is worth doing.

Where to check the figures

We do not publish tax tables or percentages: they change with each state budget, and an out-of-date number on an agency's own site is a problem rather than a typo. The sources above carry the current value.

Reviewed 2026-07-27