How to Demist a Car

Nothing is more frustrating than getting into your car and finding your windscreen misted up, especially when you’re in a hurry.

In a panic, you might start pressing every button in sight, hoping it will clear. But did you know there’s a specific method to demist your car effectively? In this guide, we’ll show you exactly how to clear your windscreen quickly and safely, so you can get back on the road without stress.

The most common reason people think cars mist up is because warm body heat in the winter mixes with the cold air in the car. While this is when it is most likely to happen, your car can mist all year round. This is caused by a difference in temperature and humidity between the air inside the vehicle and the glass.

When you enter the car in winter, your body heat and breath warm the air inside. The moisture in the air then comes into contact with the cold windows and condenses, causing the mist. In the summer months, air conditioning can cool the air inside the car, while the hot, humid air outside causes condensation on the windows. However, misting is more likely after rain or when there’s high humidity.

Yes, you must ensure you have a clear view of the road before driving.

While there is not a specific offence called “driving with a misted windscreen”, UK law requires drivers to have a clear view of the road ahead. Regulation 30 of the Road Vehicles (Construction and Use) Regulations 1986 requires the vehicle to allow the driver a full view of the road and traffic ahead, and its transparent materials must not obscure the driver's vision while the vehicle is being driven.

The Highway Code also states that drivers must be able to see before setting off and advises that windows should be thoroughly demisted. This means that driving with a significantly misted windscreen could potentially result in an offence of driving without due care and attention, depending on the circumstances.

Always fully demist your windscreen and ensure you have adequate visibility before setting off. If your windscreen becomes obscured while driving, slow down and stop somewhere safe to clear it before continuing.

Now that we know why the mist appears, here’s how to quickly clear the mist from your car windows. Follow these simple steps to restore visibility for a safer drive:

1. Turn on the Heater
   Set the heater to a warm/hot temperature and direct the airflow towards the windscreen. In winter, this helps warm the air inside the car, reducing condensation. In summer, it can help balance the temperature difference between the cool air inside and the warmer outside air.
2. Activate the Air Conditioning (AC)
   After turning the heating on, make sure to turn on the air conditioning. The AC helps remove moisture from the air inside the car, which is crucial for clearing mist, regardless of the season.
3. Use Your Car's Demist Button(s)
   Many cars come with a demist button or a defrost mode. Turn it on for faster clearance. This mode directs airflow specifically to the windscreen, speeding up the process.
4. Open the Windows Slightly
   If your car doesn’t have air conditioning or if it's not working, you can open the windows slightly to allow fresh air to circulate. This helps reduce the humidity inside the car, making it easier to clear the mist from the windows.

By following these steps, you can effectively demist your car and ensure clear visibility, whether it’s hot and humid in the summer or cold and frosty in the winter.

There are many myths surrounding the best ways to demist your car windows. With so many tips and tricks online, it’s easy to get confused about what really works.

This is actually a myth. Cold air can cause condensation to form on the windows, making the problem worse. To demist your windows effectively, you should use warm air, as this helps to increase the temperature inside the car and encourages the condensation to evaporate. Using both the heater and air conditioning is the best option for quick demisting.

While wiping with a cloth might seem like a fast solution, it is not ideal. When you wipe the windows, you're only removing the surface moisture temporarily. Additionally, wiping can leave streaks, affecting visibility. Instead, it’s best to use the car's air conditioning and heating system to remove the mist more effectively.

While older cars may not have the same advanced climate control systems as newer models, misting can happen in any car, regardless of age. The issue is because of the differences in temperature and humidity inside and outside the vehicle. That said, modern cars often come with better air conditioning systems and automatic defrosting settings, which can help manage condensation more effectively.

The JCT600 blog is full of helpful tips and advice to improve your driving experience. Check out our current article and keep an eye out for more expert advice in the future. In the meantime, explore our wide selection of new and used cars on our website and find the perfect vehicle to suit your needs!