Driving during monsoons or on rainy days is especially pleasant and enchanting, but it also brings in some challenges. Heavy rainfall can often obstruct the sight of the driver. The visibility of the road ahead can further get blocked or blurred by the fogged-up windshield. This adds to the difficulty of steering on a rainy day, and is dangerous to navigate the wet roads during such conditions. But worry not; there is a device you can rely on called a ‘defogger’ to solve this fogging issue. We will delve into what a defogger is in a car, the way it works and much more.
Meaning of a defogger and the way it works
Have you ever wondered what a defogger is in a car? A defogger is a device in a vehicle that works to remove condensed water droplets or ice from the main windshield, side windows, and rear windscreen. By doing so, it improves visibility, especially during rainy or foggy days. The device is also known as a demister or defroster. There are two types of demisters based on their working principles: primary and secondary. Before looking into the working of a defogger, we’ll dive into why the windscreens get fogged up during the rainy season in the first place.
Fogging is a phenomenon that happens when warm air comes in contact with a cold surface. During monsoon or cold climates, the vehicle's windscreen gets chilly faster, and when the surrounding relatively warm air touches this surface, condensation occurs. This results in the accumulation of tiny water droplets on the windshield's surface.
The primary defogger in a car works with the help of the vehicle's HVAC (Heating, Ventilation, and Air Conditioning) system. It draws in fresh air and dehumidifies it. The dehumidified air then passes into the heater core, where it gets heated. The dry, hot air is then passed through different vents and circulated to different areas inside the car, including the windshield. Primary defoggers mainly function to clear the front windscreens.
The secondary defogger in a car operates by restive electric heating. The glass surface of the vehicle is pasted with the filaments of heating material, and when the system gets turned on, the electric current passes through the filaments and produces heat. This heat melts the condensed water. A secondary defogger is mainly employed to clear the rear windscreen.
How can you use a defogger to demist the windshield?
A windshield defogger is a common feature of any four-wheeler. It can demist the front windscreen and clear the glass for the driver to get a better view of the road when it rains. The following steps will activate the primary defroster in your car.
- In the dashboard, you’ll find a button with a symbol that looks like a curved window with three squiggly arrows crossing it.
- Press the button just once, and the defogger of your car will get activated. The icon on the button will get illuminated when the defrost function turns on.
- Once the defogger gets activated, the hot air from the heating core of the HVAC system is channelled to the desired locations in the car, including the windshield, to clear the fogginess of the glass.
- To deactivate the defroster after use, press the same defogger button again.
How to defog car windows in the rain when the AC is on?
Do you know that apart from the defogger in the car, the vehicle’s AC can help defog the front windshield, windows and rear windscreen? You can use the AC system effectively clear the fog in certain circumstances, such as during monsoons and cold weather. Switch on the AC and increase the temperature; this will raise the heat inside the car cabin. It will result in warm air circulating inside the car and hitting the windshield. This will make the glass of the windscreen hot and causes the moisture to evaporate, clearing the surface. The car’s heater and defogging vents on the bottom of the windscreen work together to demist the glass.
Another way to defog the windshield is by dehumidifying the air inside the car cabin. You can use the AC system to accomplish this. Since a majority of the new car models come with climate controls, activating the defrost settings will automatically turn on the AC. This will dehumidify the interior air first and then warm it up by blowing out the hot air from the heater core. The heated air circulating inside the car will strike the windshield and defrost the glass.
How to defog car windows in the rain when AC is off?
Demisting the windscreen and windows is difficult in a car that has no AC system or if the AC is not working or is faulty. In such cases, a defogger can come to your help. You can follow the steps below:
- Switch the defroster on and adjust to a low setting
- Turn off the recirculate setting to allow fresh air to flow into the car
But what if both the AC and defogger are defective? You can then follow this alternative process:
- Roll down the car windows
- This allows warm air to enter the cabin
- As the interior starts getting filled with warm air, the moisture-laden air from inside will escape outside.
- This will help clear the mist on the glass
Steps to defog the rear window of your car
A clear rear windscreen is equally necessary as a front windshield. It helps the driver to see the traffic behind the vehicle when observed through the rearview mirror inside the cabin. So, fogging of the rear windscreen can hinder the view of the row of vehicles behind your car. Thus, it becomes essential to clear the fogged-up rear glass. Follow the steps detailed below to defrost the rear windscreen.
- Turn on the defogger.
- Some cars have two separate defogger buttons, one for the front windshield and another for the rear windscreen.
- If your car has a rear defrost button, use that.
- The rear defogger button can be located on the vehicle’s dashboard. It has a symbol that looks like a rectangular window with three squiggly arrows crossing it.
- Press the defrost button once
- Switching on the button will send electricity to the very fine heating wires pasted across the rear windscreen.
- Heated wire evaporates the water droplets on the glass and clears it.
- Turn on the AC and increase the temperature
- Switch on and activate the heater to defog the glass
- Roll down the windows to allow warm air to blow in
How to defog your car glass during winter?
During the winter season, the temperature outside the car’s cabin will be comparatively lower than that of the inside. This difference in temperature causes mist to develop on the windscreens and windows. This happens when the warm air inside strikes the chilly glass surface of the windshield. Follow these instructions to defog the car windows and windscreens during winter.
- Bring down the AC temperature: If the climate is too cold, lower the AC temperature to adjust the temperature inside and outside of the cabin to match. This balance will help to clear the fogged windows and windshields.
- Activate the defogger: Switch on the defroster to demist the glasses. This will start to blow out hot air into the cabin and windshield. This clears the fogged-up glasses.
- Switch off the air recirculation system: Turning the air recirculation button off will let the fresh air from outside flow into the cabin, lowering the temperature inside. This will help the mist to disappear from the windscreens and windows.
How to defog your car glass during summer?
Summers can also cause fogging of the windshields and windows because, during the hot and humid climate, the AC will always be turned on, causing the inside of the car to remain cool while the temperature is high outside. When the hot air hits the cold glass surface, the windshields get fogged up outside. To clear the mist, follow these simple steps:
- Raise the AC temperature: Heat the inside of the cabin by increasing the AC temperature. This will help to balance the temperature inside and outside.
- Turn on windshield wipers: Since the mist is outside the glass, wipers can clear it.
- Roll down the windows: This allows warm air from outside to enter the cabin and maintains a balance with the atmospheric temperature.
How to defrost your car’s windshield while driving?
While you are driving the vehicle, the most convenient way to defog the windshields is using the defroster. The defogger button on the dashboard is at a place easily accessible to the driver, so you can switch it on while steering the car. You can also follow a suitable process from the above-mentioned methods after analysing the situation. If you feel that there is a necessity to make some other adjustments inside the car, and if it is not possible while behind the wheel, then park your vehicle at a safe spot and do what’s necessary. Don’t try to wipe the glass with a cloth while driving because you may lose sight of the vehicles ahead, which can lead to accidents.
How to prevent your car windows from fogging?
Are you wondering whether it is possible to prevent the fogging up of windshields and windows? Then, the answer is yes, it is attainable. Here are some tips and tricks to prevent the mist from clouding your car’s glasses.
- Place silica balls, wrapped in a cloth, inside the cabin. They are good at absorbing moisture from the air. This will prevent fogging up of the windscreens and windows.
- Another method is the application of shaving foam on the windshields. Spread the foam evenly all over the glass and let it dry. Clean the excess foam by wiping it with a cloth. This shaving foam layer acts as a barrier and prevents moisture from building up on the glass surface.
Lastly, choosing the right car insurance is crucial. It covers losses or damages or losses to third-party property/person in the event of an accident involving your car. Additionally, car insurance protects you from legal liabilities and expenses associated with bodily injury or death of a third party.
Frequently Asked Questions
1. What is a defogger used for in a car?
Defogger is an inbuilt device in a four-wheeler that helps to remove condensed water droplets or even ice from the windshields and windows.
2. Why does my car window fog up from the inside?
Fogging up of the car windows occurs when the temperature inside and outside the vehicle varies, causing condensation of the water vapour in the air. When the weather is cold, the glass gets easily chilled, and the warm air from the passengers’ breath circulating inside the cabin causes condensation, resulting in fogged-up windows.
3. Is it necessary to have a rear defogger in my car?
Yes, having a rear defogger in the car is essential to defrost the rear windscreen. This is because a clear rear windscreen allows you to view the traffic behind you and can help prevent accidents.
4. How to turn on a defogger in my car?
There may be two defogger buttons in a car, one for the front windshield and another for the rear windscreen. Pressing the one you need once will activate the defogger.
Disclaimer: The information provided in this blog is for educational and informational purposes only. It may contain outdated data and information regarding the Insurance industry and products. It is advised to verify the currency and relevance of the data and information before taking any major steps. ICICI Lombard is not liable for any inaccuracies or consequences resulting from the use of this outdated information.
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