The window does not close properly, water gets in, or the glass has misted up, and the company says «the warranty is over» or does not answer at all. Before you accept that, read what the law says. This guide summarises Decree-Law 84/2021, read in the text published in the Diário da República, and shows what to do, in order, so you do not lose rights through a missed deadline or missing proof.
We are not lawyers. This is information, not legal advice. At the end we list what we could not confirm.
In short
| Question | What the law says | Article |
|---|---|---|
| How long is the company liable? | 3 years from delivery of the goods | 12(1) |
| When does it start if the company installs? | When the installation is finished | 11(2) |
| Who must prove the defect? | In the first 2 years it is presumed to have existed at delivery. After that, the consumer must prove it | 13 |
| What about the first 30 days? | You can ask straight away for a replacement or to cancel the contract | 16 |
| How long does the company have to repair? | A reasonable time, as a rule up to 30 days | 18(3) |
| Who pays for the repair? | The company, including removing and refitting the window | 18(2) and (5) |
| How do you notify the company? | Letter, email or another means that leaves proof | 12(5) |
Does the law apply to windows?
In most cases, yes, for people buying windows for their own home. Decree-Law 84/2021 applies:
- to sales contracts between a consumer and a trader, including goods «to be made or produced» (article 3(1)(a)). Made-to-measure windows fall here;
- to goods supplied under a works contract or other service (article 3(1)(b)). Replacing windows as a «job» falls here.
A consumer is a natural person buying for purposes outside their trade or profession (article 2(g)). The decree entered into force on 1 January 2022 and applies to contracts made after that date (articles 53 and 55).
When the clock starts
The three years run from delivery. If the contract says the company installs the window, the goods count as delivered when the installation is finished (article 11(2)). So keep the date the job ended: invoice, delivery note, a message from the company saying it is done. Use the handover checklist on installation day.
What counts as a defect
The law speaks of a «lack of conformity». A window conforms if it matches what was contracted (description, type, quantity, quality, sizes and agreed features), suits the normal use of windows, and has the usual durability and safety (articles 6 and 7). What the company or manufacturer said in advertising or on the labelling also counts.
One important point for windows: if the problem comes from incorrect installation done by the company, or under its responsibility, that is also a lack of conformity (article 9). A good window badly fitted, for example letting water or air in, is covered like a faulty window.
What you can demand, and in what order
- Repair or replacement of the window, your choice, unless the chosen method is impossible or disproportionately costly for the company (article 15(1) and (2)). It must be free, done within a reasonable time and without serious inconvenience to you (article 18(2)). If the window has to be taken out, the company pays for removal and for fitting the repaired or new window (article 18(5)).
- Proportional price reduction or cancelling the contract (refund), but only in certain situations: the company did not repair or replace, did not do it in time, refused, the fault came back after repair, another fault appeared, or the fault is so serious that it justifies these remedies straight away (article 15(4)). You cannot cancel if the fault is minor (para. 6). On cancellation the company refunds within 14 days (article 20(6)).
- In the first 30 days after delivery, if the defect appears, you can ask straight away for replacement or cancellation (article 16, the so-called right of rejection).
Other useful points:
- A repair should not take more than 30 days, unless the nature of the goods, the seriousness of the defect or the work needed justify longer (article 18(3)).
- Each repair gives 6 more months of warranty, up to four repairs (article 18(4)).
- The consumer can refuse to pay the rest of the price until the company meets its duties, but not instalments that are already late (article 15(7) and (8)). Before withholding any money, ask DECO or a lawyer.
The deadlines that run against you
- Notify in writing. Notice of the defect must be given by letter, email or another means capable of proof (article 12(5)). A phone call proves nothing. The notice suspends the three-year period until the company restores conformity (article 12(4)).
- Do not let it drag on. The consumer’s rights lapse two years after notice of the defect (article 17(1)). The period stops while the goods are with the company for repair and during any out-of-court attempt to settle the dispute (article 17(2)). If the company keeps you waiting for months, keep the dates and messages.
To write the notice, use the complaint letter generator: enter the installation date, it works out which stage you are in and writes the letter with the right articles. Your data stays in your browser.
What about the manufacturer?
The consumer can demand repair or replacement directly from the manufacturer, without affecting rights against the seller (article 40). The manufacturer can object in cases set out in the law, including when more than 10 years have passed since the goods were put on the market. The manufacturer must also keep spare parts for repairs for 10 years after the last unit was put on the market (article 21). When the window brand is not the installer’s, this can help: keep the window and glass labels.
And the company’s own warranty?
An extra («commercial») warranty is only worth what is written and advertised, and must be given in writing by the time the goods are delivered, in clear Portuguese (article 43). It must say that the consumer’s legal rights are not affected. A two-year company warranty does not shorten the three-year legal guarantee.
Step by step if the window is faulty
- Document. Photos and a short dated video. If water comes in, note when and in what weather. Do not repair anything yourself.
- Gather papers. Invoice with tax number, quote, contract, warranty, photos of the finished work.
- Write to the company (email asking for confirmation of receipt, or registered letter). Say what is wrong, since when, and what you ask for (repair, replacement). Give a deadline (30 days is the law’s reference for repair).
- Wait and record. Keep every reply. If the company comes to repair, ask for a paper saying what was done and when.
- If it is not solved: file a complaint in the electronic complaints book (livroreclamacoes.pt). The company has 15 working days to reply (Decree-Law 74/2017). You can also use consumer mediation or arbitration (12 authorised centres; for disputes above 5,000 euros the company is not obliged to take part). See the summary in how to check a company.
- If it still goes nowhere: contact DECO, the Directorate-General for Consumers or a lawyer before going to court.
If you bought a new home from the developer
Buying a home from a trader has a different regime: the trader is liable for non-conformities that show up within 10 years for structural elements and 5 years for the rest (article 23). We could not confirm whether windows count as a structural element, and the decree refers to a list the Government may approve by ordinance. If the problem is the windows of a new home, the minimum period is 5 years; get legal help to find out if it is longer.
What we could not confirm
- Contracts before 1 January 2022: this text does not cover them. The old regime (Decree-Law 67/2003) was repealed for new contracts.
- Companies and condominiums: the law defines a consumer as a natural person. We did not confirm whether a condominium as buyer has the same protection.
- The labour part of a works contract: article 3 applies the decree to the goods supplied in a works contract. How the Civil Code rules apply to the work itself was not read by us.
- Wear and misuse: the text requires a «lack of conformity». Normal wear, misuse or lack of maintenance may exclude the right. We found no official list of cases.
- What is «disproportionate» or a «reasonable time» in your case: it depends on the circumstances and, in the end, on a judge.
Sources
- Decree-Law 84/2021 of 18 October (Diário da República, series 1, no. 202) (PDF; also on data.dre.pt): articles 2, 3, 9, 11 to 13, 15 to 18, 20, 21, 23, 40, 43, 53 and 55, read in the Diário da República PDF of 18.10.2021 (Portuguese only).
- gov.pt: Consumer dispute resolution and Decree-Law 74/2017: complaints book, 15 working days, mediation and arbitration.
- For other questions: Portal do Consumidor and DECO PROteste.
Text read on 27 October 2026. Laws change: always check the version in force.
What to do next
- Write the notice to the company with the letter generator.
- Before the next job, see warranties and certificates and the checklist before hiring.