If you do not read Portuguese, replacing windows here means deciding on papers you may not follow: a quote, a condominium rule, an invoice. This guide collects what the rules say for an owner, what to get in writing and which Portuguese words you will hear. It recommends no company. We are not lawyers, and quotes from Portuguese sources are our translation.
1. Three permissions to check first
The town hall (câmara municipal). Since 1 October 2026, Decreto-Lei 108/2026 exempts from licence and prior notification the replacement of window frames with more energy-efficient ones, if the geometry is kept and the exterior finish is identical to the original (article 6-A(1)(j)). Listed buildings are excluded. Even when exempt, the owner tells the câmara up to five days before the work starts and names who will do it (article 80-A(1)). If the colour or design changes, ask first. See can I replace my windows?
The 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, for works that change the architectural line or the aesthetic look. A new window that looks the same from outside does not seem to need it, but read the condominium rules and tell the administrador. A different colour, material or design: wait for the decision in writing. From abroad, write to the administrator with photos and the technical sheet and ask for it to go on the next agenda.
The tenant. In a let home, the landlord does conservation works unless the contract says otherwise (Civil Code, article 1074(1)). For improvements, agree in writing.
2. What it costs
We give no average of our own. The price page collects the figures published on 19 October 2026. For example, Habitissimo gives €120 to €300 per m² for installed PVC windows, average €210/m². No source says how it measured that average, and sources disagree. Only a written quote is a price.
3. VAT, the invoice and the NIF
- VAT (IVA) is 23%. A 6% rate applies to renovation works in homes used as housing (item 2.27 of the VAT Code). Under the tax authority’s Circular 30135 it must be a works contract with a price agreed in advance, it does not cover materials unless they are 20% or less of the price, and above 20% the invoice must separate labour from materials. The invoice must name the owner and the property. We found no ruling about windows. See window grants and VAT.
- The NIF (número de identificação fiscal) is the Portuguese tax number. The tax authority (AT) says buyers should ask for an invoice on every purchase and ask for their NIF to be entered. If it was not, you can register the invoice later in the e-Fatura app by scanning its QR code. We found no IRS deduction for windows, so the NIF mostly matters on the invoice itself and as proof of purchase for a claim.
- No NIF yet? The AT says a foreign citizen can ask at a Serviços de Finanças office, or online through a legal representative holding a power of attorney. It is then granted as non-resident. Whether a non-EU non-resident also needs a tax representative: sources differ, ask the AT.
4. Grants: what to expect
On 22 October 2026 no national application was open to all private owners. Watch the Vale Eficiência voucher (applications closed on 31 October 2024; the press says eligible families would be contacted from 15 October 2026, not confirmed officially), a Banco Português de Fomento loan that must open by 12 December 2026, and town-hall programmes. Of the schemes we read, those with stated conditions mostly ask for a permanent home, the social electricity tariff or a Portuguese IRS bracket, so second-home and non-resident owners may not qualify. Read the rules before you buy: window grants.
5. Is the installer allowed to do the work?
According to gov.pt (updated 27 March 2026), companies and self-employed workers need an IMPIC private-works contractor’s certificate to carry out private works. IMPIC says the certificate covers works up to €40,000 excluding VAT, and the alvará covers works by value class. In Lei 41/2015 (the version of 14 June 2018), “obra” includes altering, repairing and conserving buildings (article 3(k)), and article 29(1) says owners whose works are exempt from municipal control must make sure a duly licensed company does them. That points to window work needing a title, but we could not confirm with IMPIC. Ask for the company’s IMPIC number: how to check a company.
6. Comparing quotes
- Measure and list each window: size, how it opens, shutter.
- Send every company the same list (how to ask for a quote). DECO PROteste advises three quotes for the same type of window, with VAT shown separately.
- Ask each quote to say, per window, the frame brand and model, glass and colour, and whether removal of the old windows, rubble, finishing and the shutter box are included.
- Compare price per window and per m², installed and with VAT, with the quote checker or the quote comparison.
- Airtight windows change ventilation: see the ventilation check.
If you are away, name someone who can open the door and write it into the quote.
7. What to put in writing
- Company name, NIF and address; your name, NIF and the property.
- Each window: size, opening, frame, glass, colour.
- What is included, the total with VAT, the VAT item named, labour and materials on separate lines.
- Each payment tied to a stage. DECO PROteste says 50% to confirm is usual and more is a warning sign.
- Start and end dates, and who installs.
- Guarantee periods for frame, glass and installation, and how to claim: warranties.
- An invoice with your NIF.
Under Lei 41/2015 (article 26), private-works contracts above 10% of the class 1 limit must be written or are void. By IMPIC’s figures that is about €20,000 (our arithmetic: €40,000 is 20% of class 1). Put it in writing anyway. Ask for the contract in Portuguese plus an English summary, and do not sign what you have not had translated.
8. Guarantee and complaints
Decreto-Lei 84/2021 makes the seller responsible for defects that show up within three years of delivery (article 12(1)), presumed to have existed at delivery in the first two (article 13(1)). If the sale includes installation by the seller, the goods count as delivered when it is finished (article 11(2)), and incorrect installation by the seller is a defect (article 9). Notify by letter, email or any provable means (article 12(5)). The consumer is a person acting outside a business (article 2(g)). Keep the invoice as proof of purchase (gov.pt, updated 7 October 2026).
To complain, use the electronic complaints book at livroreclamacoes.pt. Its FAQ (read 23 October 2026) says it is in Portuguese and English, free, and needs only a valid email. For the dispute itself, gov.pt (updated 15 October 2026) lists 12 consumer arbitration centres, for disputes up to €5,000, with a 90-day target.
9. Portuguese you will hear
| Portuguese | In English |
|---|---|
| janela de correr / oscilobatente | sliding window / tilt-and-turn window |
| caixilho | window frame, sash |
| vidro duplo | double glazing |
| orçamento | quote |
| empreitada | works contract: a job for an agreed price, not paid by the hour |
| condomínio / administrador | the owners’ community / the person who manages it |
| NIF / IVA | tax number / VAT |
| fatura / sinal / garantia | invoice / deposit / guarantee |
More terms: glossary. Useful sentences:
- Pode enviar um orçamento detalhado, por escrito, com o preço por janela? (A detailed written quote, with a price per window?)
- O preço inclui IVA? A que taxa? (Is VAT included? At what rate?)
- Pode passar a fatura com o meu NIF e a morada do imóvel? (Invoice with my NIF and the property address?)
What I could not confirm
- Whether a non-EU non-resident needs a tax representative to get a NIF.
- Whether the 6% VAT applies to windows, to a second home or to a holiday let.
- With IMPIC, whether window replacement needs a contractor title, and whether Lei 41/2015 changed after 2018.
- Whether Decreto-Lei 84/2021 applies if the contract is a works contract, or if you let the home professionally.
- What the Portal do Consumidor (consumidor.gov.pt) offers in English: its page had no readable text.
Sources
- Our replacement rules (Decreto-Lei 108/2026, Civil Code, 23 October 2026), grants and VAT (22 October 2026) and price (19 October 2026) pages.
- AT: e-Fatura FAQ and AT: NIF for foreign citizens, read 23 October 2026.
- gov.pt: contractor’s certificate, IMPIC and Lei 41/2015, consolidated 2018: articles 3, 25, 26, 29. Read 23 October 2026.
- Decreto-Lei 84/2021, gov.pt: guarantee and gov.pt: consumer disputes. Read 23 October 2026.
- Livro de Reclamações FAQ and DECO PROteste: 7 precautions.
What to do next
- How to check a company and questions for the installer.
- Old flat in Lisboa or Porto? See building age by parish: Lisboa, Porto.