Do I need a council licence to replace my windows?

Under Decreto-Lei 108/2026, replacing window frames with more efficient ones, with the same geometry and an exterior finish identical to the original, is work exempt from a licence and from prior notification. You must inform the câmara up to five days before starting. If the colour, material or design changes, ask the câmara. Listed buildings are out.

Can I change the colour of the windows of my flat?

Article 1422 of the Civil Code asks for the prior authorisation of the owners' meeting, by a majority of two thirds of the total value of the building, for works that change the architectural line or the aesthetic look. Another colour may be the case: talk to the administrator before ordering.

Can the condominium forbid me to replace the windows?

If the window looks the same from outside, the law does not seem to ask for authorisation, but the constitutive deed and the condominium rules may have rules of their own. If it changes the look of the building, you need the meeting's authorisation.

Who pays for the windows in a rented home?

According to article 1074(1) of the Civil Code, the landlord carries out conservation works, unless the contract says otherwise. A broken window is usually conservation. Improvements are agreed in writing. Read the contract.

Does the exemption apply to a listed building?

No. Decreto-Lei 108/2026 leaves out listed buildings or buildings being listed. In protection zones of listed buildings, replacing frames with an identical exterior look may be exempt.

When does the new rule come into force?

According to Decreto-Lei 155-B/2026, which changed article 13 of Decreto-Lei 108/2026, on 1 October 2026. So the rule already applies.

Can I replace my windows? Licence, condominium, tenancy

In short

Under Decreto-Lei 108/2026, replacing window frames with more efficient ones, with the same geometry and an identical exterior finish, is exempt from a licence and from prior notification. The câmara must be informed up to five days before. Listed buildings are left out.
In a building with a condominium, article 1422 of the Civil Code asks for the prior authorisation of the owners' meeting, by two thirds of the total value of the building, if the work changes the architectural line or the aesthetic look: a window with another colour or design may be the case.
In a rented home, conservation works are the landlord's, unless the contract says otherwise (article 1074(1)). Improvements are agreed in writing.
The quiz shows what applies to your case and has a ready letter for the administrator.

Can I replace my windows?

Answer 4 questions. We check what Decreto-Lei 108/2026, the Civil Code and the tenancy law say about your work. Your values stay in your browser.

Where is the window?

A house, no condominium

A flat in a building with a condominium

A rented home: I am the tenant

Will the new window look the same from outside?

Yes, the same from outside

No: the colour, material or design changes

I do not know

Same shape and proportions of the glass and the frame, and the same exterior finish (colour and look).

Is the building listed, or in a protected zone?

It is in the protection zone of a listed building (for example, a historic centre)

The building itself is listed or being listed

I do not know

What the law says for your case

Town hall (câmara municipal)May be exempt
Under Decreto-Lei 108/2026 (article 6-A(1)(j)), replacing window frames with ones that promote energy efficiency, with the same geometry and an exterior finish identical to the original, is work exempt from a licence and from prior notification. You must inform the câmara up to five days before starting (article 80-A). The law comes into force on 1 October 2026 (Decreto-Lei 155-B/2026), so it already applies.
CondominiumInformation
Article 1422 of the Civil Code forbids owners to harm, with new works, the safety, the architectural line or the aesthetic look of the building. Works that change them need the prior authorisation of the owners' meeting, by a majority representing two thirds of the total value of the building (paragraph 3). If the window looks the same from outside, that authorisation does not seem to be needed, but the constitutive deed and the condominium rules may have rules of their own: read them and tell the administrator.
What to do nextInformation
Talk to the administrator before asking for quotes. Use the letter below, attach a photo, the drawing and the technical sheet of the new window, and ask for the decision in writing.

Letter to the administrator (in Portuguese)

It is already in Portuguese, because the administrator reads Portuguese. Copy it and replace what is in square brackets.

Exmo. Senhor Administrador do Condomínio do prédio sito em [morada],

Eu, [nome], proprietário da fração [letra/andar], venho comunicar que pretendo substituir as janelas da minha fração por janelas novas, mais eficientes do ponto de vista energético.

Características da janela nova: [material do caixilho], cor [cor], [número] folhas, com [descrição do desenho e da divisão dos vidros]. Junto fotografia da situação atual, o desenho e a ficha técnica da janela proposta.

Se a obra modifica a linha arquitetónica ou o arranjo estético do edifício, o artigo 1422.º, n.º 3, do Código Civil exige a autorização prévia da assembleia de condóminos, aprovada por maioria representativa de dois terços do valor total do prédio. Por isso, peço que o assunto seja incluído na ordem de trabalhos da próxima assembleia e que me seja comunicada a decisão por escrito.

Fico à disposição para prestar qualquer esclarecimento. Só iniciarei a obra depois da decisão.

Com os melhores cumprimentos,
[nome], [telefone], [email]
[data]

This is a guide, not legal advice: the rules change and each building and each câmara may have rules of its own. Check with your câmara and the administrator.

«Can I replace the windows of my home?» has three answers, depending on whether you are in a house, in a flat with a condominium or in a rented home. Each case has a different body to ask: the town hall (câmara municipal), the owners’ meeting or the landlord. This guide gathers what the law says and gives you a ready-made letter for the building administrator.

Use the quiz above first: it asks 4 questions and shows what applies to your case.

The town hall: licence and notice

Since 2026 there is a new rule. Decreto-Lei 108/2026 (Diário da República, 29 May 2026) puts among the works of minor urban-planning relevance, exempt from a licence and from prior notification, «replacing the window frames of the openings with ones that promote energy efficiency, provided the geometry and the volumetric relation of the different components of the frame are kept, giving an exterior finish identical to the original» (article 6-A(1)(j)). This also holds in protection zones of listed buildings.

Listed buildings, or buildings being listed, are left out (article 6-A(2)(a)).

Even when exempt, the work is not a surprise: up to five days before the work starts, including works exempt from a licence or prior notification, the owner informs the câmara and says who will carry it out (article 80-A(1)).

Two notes of caution:

A different colour, material or design. The exemption asks for an identical exterior finish and the same geometry. If the colour or the design changes, we cannot say it is exempt: ask the câmara before ordering.
The date. Decreto-Lei 155-B/2026 of 31 July changed article 13 and set the entry into force of Decreto-Lei 108/2026 on 1 October 2026. So the rule already applies.

The condominium: the meeting and the colour of the windows

Article 1422 of the Civil Code deals with the limits owners have between themselves. It says they are especially forbidden to «harm, either with new works or by lack of repair, the safety, the architectural line or the aesthetic look of the building» (paragraph 2(a)). And it adds: works that change the architectural line or the aesthetic look «may be carried out if the prior authorisation of the owners’ meeting is obtained, approved by a majority representing two thirds of the total value of the building» (paragraph 3).

In practice:

A new window that looks the same from outside (same colour, same design): the law does not seem to ask for the meeting’s authorisation. Still, read the constitutive deed and the condominium rules, and tell the administrator.
A window with another colour, material or design: it may change the aesthetic look. Then you need the prior authorisation of the meeting, by two thirds of the total value of the building. Do not order before the decision.
Replacing all the windows of the building at once (for example, to make them uniform): if it is work on the common parts, article 1425 also applies, which asks for the approval of the majority of owners, representing two thirds of the total value of the building.

The list of common parts in article 1421 speaks of structure, load-bearing walls, roof, entrances and general installations, and does not name window frames. The constitutive deed decides whether a window is a common part or belongs to the flat: read it.

Use the letter in the quiz: it asks the administrator to put the matter on the agenda, with the photo, the drawing and the technical sheet of the new window.

A rented home: who pays and who decides

A broken or worn window. According to article 1074(1) of the Civil Code, the landlord carries out the conservation works, ordinary or extraordinary, unless the contract says otherwise. That is how the Porto Court of Appeal reads it on 10 July 2024 (case 1809/22.0T8MAI.P1). Ask the landlord in writing and read the contract.
An improvement (a window that still works, but we want more insulation or less noise). As a rule, the tenant only does works with the landlord’s written permission or if the contract allows it. We did not confirm the text of this rule in an official source: read the contract and agree everything in writing, including who pays.
If the building has a condominium, the landlord is the one who talks to the administrator.

What to ask and keep

The installer: will the new window look the same from outside? Ask for the description in the quote (shape, colour, exterior finish). Use the quote checker.
The câmara: is my window covered by the exemption in Decreto-Lei 108/2026? Is the building listed?
The administrator: do the rules or the constitutive deed say anything about windows? Ask for the decision in writing.
Keep the letter, the answers, the technical sheets and the invoices. If you later apply for a grant, you will need them: see the guide to window grants.

What I could not confirm

The text of article 1074(2) of the Civil Code on the tenant’s works.
Whether the outside window frames are common parts or belong to the flat: it depends on the constitutive deed.
Each câmara’s rules for historic zones, and each condominium’s rules.
The Civil Code text comes from a copy with the wording of Decreto-Lei 267/94: check the version in force in the Diário da República.

Sources

Ordem dos Arquitectos: Decreto-Lei 108/2026 of 29 May (copy of the Diário da República): articles 6-A (paragraph 1(j); paragraph 2) and 80-A(1). Text read on 23 October 2026.
Diário da República: Decreto-Lei 155-B/2026 of 31 July: sets the entry into force of Decreto-Lei 108/2026 on 1 October 2026. Text read on 23 October 2026.
Mapfre: Civil Code, horizontal property: articles 1421, 1422 and 1425, with the wording of Decreto-Lei 267/94. Read on 23 October 2026.
Porto Court of Appeal, 10 July 2024, case 1809/22.0T8MAI.P1: quote of article 1074(1) of the Civil Code.

What to do next

See also replacing old windows and the guide on how to check a company.
Get an idea of the price with the calculator.
Could you get help paying for new windows? Take the window grants quiz.
Want wood-look PVC windows? See the condominium’s approval.

Can I replace my windows? Town hall, condominium and rented homes