Some may argue as to what the quickest way to defog a vehicle’s windows is, so today we’re here to share what we’ve found to be the most efficient ways to clear your vision. Whether you’re defogging your windows first thing in the morning, keeping the fog at bay while driving, or trying to decide if using the “recirc” and “A/C” buttons is the right thing to do, we’ve got you covered!
Why do vehicle windows fog up?
It all has to do with the temperature and the air’s moisture content. When the weather is cold, any moisture in the air inside your vehicle turns to condensation when it hits the air next to the windows that’s below the dew point. The dew point is the temperature to which air must be cooled to become saturated with water vapor. The condensation then makes the windows foggy.
The opposite happens on a hot day. The windows will fog up when the hot air outside your car reaches the dew point against your windshield after it's cooled by your AC system. Not being able to see out your windows is dangerous, so it’s important to know how to defog your windows no matter the weather.
What is the fastest way to defog your vehicle windows?
This technique relies on creating an optimal environment inside the vehicle, aiding in the moisture removal process. Start up your vehicle and turn the heater on. Use the defroster setting and turn the heater up all the way to absorb excess moisture within your vehicle. Hot air can hold more moisture, so this works better than blasting cold air. Putting the heat up to max will also help to melt any frost or ice that has built up on your windshield.
Once the heat is turned up, activate the A/C. Turning on the A/C activates a setting on your vehicle’s A/C system that helps dry the air within the interior faster. The goal is to make the air inside the vehicle as hot and dry as possible, which defogs the windows faster.
Avoid using the recirculation button. Fresh, dry air needs to enter the vehicle and using the recirculation button will keep the stale air trapped inside. By keeping the recirculation button switched to off, the absorption capacity increases and will allow the saturated air trapped within to dry quickly by adding new air to the mix.
Roll down the windows as well. This will exchange the humid air inside the vehicle with dryer outside air and help speed up the process. Lastly, scrape and excess ice and frost from all the windows. You should be fully clearing your windows before driving for maximum visibility, and removing this ice and frost manually will speed up the process of heating the air within the vehicle. If you leave this step until last, the ice and frost should clear fairly quickly due to the heat building inside.
How do you defog your vehicle windows when it’s raining?
Your windows can also fog up when it’s raining, which can be dangerous if you’re in the middle of driving and you start to lose visibility due to fogged windows. If the windows do start to fog up while you’re driving, no matter the weather condition, you should follow two of the steps that you would if you were starting your car up in the morning: turn the A/C on and keep the air recirculation off.
Defogging your windows is a fundamental step to driving safely in the rain amongst the other best practice that keep you safe.
The main goal is to remove moisture from the air and these two actions will get you there. Turning on the air conditioner engages the help of the system’s coils to remove moisture from the air. Turning the air recirculation off will bring in drier air from outside versus the air that has built up inside the vehicle. Many drivers, in their hunt for a fog-less window, will activate anything and everything that’s available on the console, but activating the air recirc button can mean an increased amount of fogging since there is no new air being added into the interior of the vehicle.
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Keeping your vehicle windows clear of fog is an important skill, especially when you’re driving throughout the frequently changing weather conditions in British Columbia. Now that you’ve read through our quick guide for defogging your windows, you’ll be ready for any amount of fog that comes your way!