Guides and tips
Damp in the car
If your windows fog up in autumn and the interior starts to smell musty due to damp, take action straight away – because damp in your car means more than just poor visibility.
Eliminate moisture in the car
Guides and tips
If your windows fog up in autumn and the interior starts to smell musty due to damp, take action straight away – because damp in your car means more than just poor visibility.
Eliminate moisture in the carIn autumn and winter, moisture often finds its way into the car – through water tracked in from outside, blocked drains or porous seals. The result: misted-up windows, a musty smell and, in extreme cases, mould or rust. TÜV NORD explains the typical causes behind this and how you can best prevent it.
Many drivers are familiar with the problem: in autumn, the windows mist up more quickly because it gets cooler and more humid. The reason for this is that cold air can hold less moisture than warm air. That is why moisture condenses on the cold windows, particularly at night.
Before setting off in the morning without being able to see properly, first switch the fan from recirculation to fresh air intake and direct the airflow at high speed towards the windscreen. Also, set the heating to warm and keep the windows closed. So if you’re wondering, ‘Do I need cold or warm air when my windscreen is fogged up?’, the answer in autumn is always: warm air!
If you have air conditioning, switch that on too, as it dehumidifies the interior. If none of this helps, you should check your ventilation system and, if necessary, properly dry out your vehicle.
In autumn and winter, moisture tends to build up on cold windows – cold air holds less water, which leads to condensation, particularly at night, and impairs visibility.
Switch the fan from recirculation to fresh air and set it to the maximum setting with warm air directed towards the windscreen. Avoid using the recirculation mode, as this merely circulates existing moisture within the cabin.
If your vehicle has air conditioning, use it to effectively dehumidify the air inside the cabin – ideally when outside temperatures are around 4–6°C, using the defrost function if necessary.
A dirty cabin air filter prevents air circulation and leads to dampness inside the car – it is advisable to replace it annually or at the latest after 15,000 km.
In addition, rain drains in the engine compartment, as well as door and sunroof drains, should be checked regularly for leaves or blockages. If these are blocked, water can seep in and subsequently accumulate inside.
In older cars in particular, the seals on doors, sunroofs or windows are often worn out and allow moisture to get inside. You can counteract this with special care products such as talcum powder or silicone oils. This is an effective way to prevent moisture damage.
Additional dehumidification can be achieved using aids such as desiccant sachets (silica gel sachets), cat litter in cloth bags or salt – particularly in older vehicles or those without air conditioning. These methods absorb moisture and significantly reduce condensation.
Wet clothes, shoes or jackets bring a lot of moisture into the car. Therefore, shake your shoes out thoroughly before getting in and, if necessary, place wet jackets in the boot. Fabric mats absorb water, whereas rubber mats are easier to clean and retain less moisture.
Damp floor mats should be removed immediately and dried, or replaced with newspaper.
Clean, well-cleaned windows are much less likely to fog up than those on which a film of nicotine, plastic fumes or other residues has built up.
Cold air holds less moisture than warm air. In the autumn and winter months, moisture in the air – for example, from exhaled breath or damp clothing – condenses on the cold windows.
In autumn and winter, warm air is much more effective: it can absorb more moisture and dries the windows more quickly. Cold air, on the other hand, contains moisture and promotes condensation – a common mistake when using the recirculation mode. You should therefore always use warm fresh air and direct it specifically at the windscreen.
Condensation, damp and mould are not only unpleasant, but can also cause long-term damage to your car. Our tips show you how to effectively prevent damp and keep your vehicle dry.
