Car Defoggers and How to Use Them

Posted on: Feb 27, 2024 | 3 mins | Written by: HDFC ERGO Team

Car Defoggers and How to Use Them

It’s common to notice water droplets accumulating on your car's windows and windscreen or windshield, especially during monsoons and winters. A significant temperature difference between the interior and exterior of the vehicle causes this. When the warm air inside the car comes in contact with cold surfaces like windows and windscreens, it causes condensation or fogging and hampers the driver's visibility. This may lead to accidents. So, to combat this issue of clouded view, automotive manufacturers install defoggers in cars. You will also need comprehensive car insurance to compensate for any unfortunate events on the road during such rainy or foggy days.

What are Car Defoggers?

Defoggers are essentially guardians of visibility for car drivers. Fogged-up windows are problematic because the low visibility isn’t just an unpleasant experience, it’s also a safety concern. Due to poor visibility, you may lose track of direction and get into an accident. A defogger in a car works against condensation by introducing warm air and catalysing evaporation. Most cars typically have two defoggers, one for the front windscreen and another for the rear windscreen.

Types of Car Defoggers

Car manufacturers install specialised systems, front, and rear defoggers, to prevent fogging on glasses. Both types of defoggers function differently. Here’s what to know about them:

Front defogger

The front windscreen offers the main point of view for the driver. Any distortion in their visibility due to fog, rain, snow, and the like could be a safety threat for the driver and passengers. The front defogger assumes a crucial role here by ensuring the driver has maximum visibility and safety while navigating congested cities and serene countryside roads.

The front demister is a primary defogger. It utilises the car's heating, ventilation, and air conditioning (HVAC) system to perform its job. Upon activation, the HVAC system directs warm air to the vents installed at the base of the front windscreen. As the warm air spreads across the glass, it increases the temperature of the surface, causing the water droplets to evaporate.

Rear defogger

Drivers must be aware of vehicles coming from all directions, including those behind them. Hence, the rear windscreen is as vital as the front windscreen, since,an unclear rear view could pose problems in changing lanes or manoeuvring while reversing the vehicle. While both front and rear defoggers ensure vision clarity, they operate slightly differently.

The rear defogger is a secondary one and works on the principle of electric heating. This demister takes the form of thin lines (composed of a conductive material) on the rear windscreen. When you activate the rear defogger, electricity passes through these (almost invisible) lines and heats them, dissipating the fog on the windscreen.

How to Use Car Defoggers?

Now that you know the difference between the front and rear defogger in a car, here’s a general outline of how to use them:

Find the button

Look for the defogger button on the car’s dashboard. The button would have a symbol with a rectangle containing lines inside or wavy lines.

Activate the defogger

Pushing the defogger button activates it. Some cars have an indicator light that turns on upon system activation. If your four-wheeler has separate buttons for the front and rear defogger, press the one you need.

Change the temperature

In warm conditions, lower the vehicle's temperature for the front defogger to remove the warm fog effectively. In cold conditions, increase the temperature.

Switch off air recirculation

Turning off the air recirculation mode ensures fresh air from outside enters the car, clearing out the fog more effectively.

Adjust the fan speed

Increasing the speed of the fan accelerates the defogging process. You can lower the fan speed after the fog clears up.

Monitor duration

Some rear defoggers work for a specific duration and turn off automatically once the time lapses. If there’s still some uncleared fog, you may have to activate the rear defogger again.

Turn off the system

Once all the fog on the windows and windscreens is gone, switch off the defogger to avoid further energy consumption and maintain an optimum temperature inside the car.

You can also defog using your car’s AC or without it. For the former, adjust the temperature and circulation settings of the AC to balance the temperature inside and outside the vehicle. To defog without using the AC, simply roll down your windows to facilitate a quick air exchange.

How to Prevent Fogging?

Some measures can help prevent the formation of fog. These include:

Silica gel

Silica gel beads are hygroscopic, they absorb moisture from the air. Keeping these inside a sock and placing it in your car can reduce humidity.

Shaving cream or foam

This unconventional hack can be a game changer in preventing fogging. Applying a thin layer of shaving cream or foam on the windscreen creates a barrier between the surface and the moisture in the air. Clean the interior of the windscreen using a dry towel with shaving cream on it. Wipe out the residual cream, if any, with another dry towel.

Best Defogger Maintenance Practices

Considering how crucial defoggers are for driving, it’s necessary to maintain them to the best of your ability. Here are some ways to make sure your defoggers remain in top shape:

- Ensure the electrical connections of the rear defogger aren’t loose or corroded.

- Clean the windshield regularly to eliminate any dirt and grime that may accumulate and interfere with the smooth functioning of the defogger.

- Check the vents of the car, especially those near the windshield, for dust blockage. Frequent cleaning of the vents can ensure better airflow.

Conclusion

Defoggers in cars play a significant role in ensuring one has a smooth, safe, and enjoyable driving experience across varying seasons and terrains. It’s safe to say that every driver, without exception, must know how to use and maintain defoggers appropriately. Similarly, every four-wheeler owner must have a car insurance policy to protect themselves against financial losses. While third party insurance is mandatory, we suggest you get comprehensive insuranceto have protection against third-party liabilities and damages to your vehicle caused by an accident. Nowadays, you can purchase car insurance online .

Frequently asked questions

1) Do defoggers impact the car’s battery?

Rear defoggers use electrical power but have minimal impact on the vehicle's battery under regular operation. However, extensive use of the defogger could drain the battery.

2) Are defrosters and defoggers different?

Yes, while defrosters remove ice or frost from the exterior of the car’s windows, defoggers clear out the condensation on the interior of the windows.

3) How long does it take to defog car windows or windscreens?

There’s no set duration. The time a defogger needs to clear the windows or windscreens depends on factors like humidity, temperature, and the defogging system’s effectiveness.

Disclaimer: The above information is for illustrative purposes only. For more details, please refer to the policy wordings and prospectus before concluding the sales.

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