Quick answer: to demist the car windscreen, switch on the air conditioning with the temperature high, direct the air to the windscreen and turn off recirculation. To clean it, use a car-specific glass cleaner and two microfibre cloths. As for stickers, none is mandatory on the glass today. And the price of a windscreen depends mostly on the type of glass and on the driver-assistance camera.
This guide covers what a driver in Portugal needs to know about car windows, from foggy January mornings to the quote for a new windscreen.
How to demist the car windscreen
The glass fogs up on the inside when warm, humid cabin air touches the cold glass. It happens mostly in winter, with wet clothes from the rain, damp mats and several people breathing inside the car.
The fastest way to fix it:
- Switch on the air conditioning (A/C button). The compressor dries the air, even with the temperature at maximum.
- Turn up the temperature and the fan and select the windscreen air outlet.
- Turn off recirculation so that drier outside air comes in.
- Switch on the rear window demister and, if the car has it, the mirror heaters.
- For the first few minutes, open a window slightly so the moisture escapes faster.
Avoid wiping the glass with your hand or sleeve: it leaves grease, which fogs up again and causes glare at night.
Why is my car windscreen always fogged up?
If it happens every day, look for the source of the moisture. The most common causes are wet mats or carpets, a dirty cabin filter, door seals that let water in and greasy inner glass, where moisture sticks more easily.
Clean inner glass fogs up less. Anti-fog products are also sold in accessory shops and hypermarkets; they help, but they don't replace cleaning or the air conditioning.
How to clean the car windows
The outside and the inside need different care. Outside, the glass collects dust, insects, tree sap and limescale from water. Inside, a greasy film builds up from the dashboard plastics, especially when the car sits in the summer sun.
Outside:
- Wash first with water and car shampoo, so you don't drag sand across the glass.
- Apply a car-specific glass cleaner and dry with a microfibre cloth.
- For stubborn marks, detailing shops use a clay bar with lubricant.
Inside:
- Spray the product onto the cloth, not the glass, so the dashboard stays dry.
- Wipe with one cloth and dry straight away with another clean, dry one.
- Avoid ammonia-based products if the car has tinted window film: they can damage it.
Wiper blades: when to replace them
Worn blades leave streaks, make noise or judder on the glass. Sand stuck to the rubber also scratches the windscreen over time. Many drivers replace them once a year, before winter, but the best sign is the blade itself: when it stops wiping cleanly, it is time.
Before buying, check the length of each blade (driver and passenger blades are usually different) and the type of fitting. Keep the reservoir filled with screen wash too; plain water leaves marks and can freeze in winter inland.
Which stickers are mandatory on the car windscreen?
Today, none. The three stickers that were stuck on the windscreen for years are no longer required:
- Insurance: displaying the sticker stopped being mandatory on 11 July 2023, under Law no. 32/2023. The police check the insurance by the number plate. To check whether a car is insured, see how to know if a car has insurance in Portugal.
- Inspection: Decree-Law no. 144/2012 ended the windscreen vignette. Proof is the inspection form, which must be kept in the car. The deadlines are in our guide on when to take your car for inspection.
- Road tax: the old car tax sticker disappeared with the IUC, which is paid on the Portal das Finanças and has no sticker.
The Via Verde toll tag is not a mandatory sticker. If you use one, fix it where its instructions say, usually behind the rear-view mirror, out of the line of sight.
How much does a windscreen cost?
There is no single price. The cost of a new, fitted windscreen varies a lot from car to car, and glass workshops quote by number plate. What weighs most on the bill:
- Type of glass: original from the car maker or equivalent, made to the same specifications by automotive glass manufacturers. The equivalent is usually cheaper.
- Equipment in the glass: rain and light sensor, heating, an acoustic layer or a head-up display area make the glass more expensive.
- Driver-assistance camera: if the car has a camera behind the mirror (automatic braking, lane departure warning), it must be calibrated after the replacement. That is extra work and should be in the quote.
Ask for two or three quotes and always check whether they include calibration, the type of glass and a fitting warranty.
Repair or replace?
A small chip can often be repaired, which is cheaper and quicker. Workshops usually agree to repair when the damage fits within a 2-euro coin, is away from the edge of the glass and is outside the driver's field of view. A crack tends to grow with cold, heat and potholes, so it is best dealt with early.
Broken glass in the driver's field of view can also cause problems at the periodic inspection.
Does insurance pay for the windscreen?
Only if the policy includes isolated glass breakage cover («quebra isolada de vidros»). It is optional cover and not part of compulsory third-party liability insurance. Terms vary: cover limit, excess, which windows are included and whether a claim affects your no-claims bonus. Read your policy terms or ask the insurer; the ASF explains motor insurance cover on its consumer portal.
If the glass broke in an accident with another car, it is a different case: see what to do after a car accident.
When buying a used car, look at the glass
About half of the more than 10,000 cars for sale on AUTO.MOTO.pt are from 2018 or earlier, and on a car that age it is worth looking closely at the windscreen. Before closing the deal, look at the glass against the light, check for chips in the driver's area and make sure the camera and sensors work with no warnings on the dashboard.
Take the chance to check the chassis number: on many cars it is visible through the base of the windscreen. We explain what a car's VIN is and what it is for. When you are ready, compare prices among the used cars for sale on AUTO.MOTO.pt.
Frequently asked questions
Is it better to demist the glass with hot or cold air?
With the air conditioning on, what matters is dry air. Warm air speeds up evaporation, so A/C with a high temperature is the fastest combination. Without air conditioning, use outside air and open a window slightly.
Is the insurance sticker still mandatory on the windscreen?
No. Since 11 July 2023 displaying it is no longer mandatory and there is no fine for not having the sticker. Insurance itself is still compulsory.
Can I drive with a cracked windscreen?
A small crack outside the field of view does not stop you driving, but it can grow and should be checked as soon as possible. If it blocks the driver's view, it compromises safety and can cause problems at inspection.
How often should I replace the wiper blades?
As a rule, when they stop wiping cleanly, make noise or leave streaks. Many drivers do it once a year, before the autumn rains.
