What they don't tell you about before buying an EV: Fogging windows

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Driver8

Well-known member
Joined
Sep 29, 2020
Messages
79
Location
Seattle
We've had our used 2017 S Leaf for about 6 months now, and one of the things that has popped up as a bit of a surprise is how often/rapidly the windows fog up in the car. Obviously this is something a bit different in EVs compared to ICE vehicles, since there is minimal heat being produced and less air needed to "cool" the engine. It's pretty easy to defrost, but keep in mind that in the winter your options are to defrost without the AC or heater (no heat pump) on (which preserves vehicle range, but blasts you with pretty cold air), or use them with the defrost and lose some range. Nothing we haven't been able to plan for, and it really hasn't caused us to have a negative view of the car. It's just one of those things switching to an EV that we wouldn't have thought of and have had to adjust our frame of mind a little bit, when driving.

Just something to keep in mind when you've gotten your first EV.
 
Give this a try...

Hit the front defrost button, which will turn on both the heat and AC buttons. Next, turn off both the heat and AC buttons. Doing that blows fresh air on to the windshield.

After trying a lot of different settings, including partial recirculation, I find this one works best for me. However, Vancouver during winter tends to be single digit C temps (35 - 50 F) with rain, so that setting likely won't work as well in colder climates where the windshield will ice up without any heat turned on.
 
Also, I've found keeping the floors as dry as possible helps quite a bit. We have Weathertech floor liners so it's relatively easy to wet vac the water occasionally if you had carpet I'm not sure how well this would work. Keeping the floor as dry as possible reduces water evaporation which reduces the overall humidity in the car which helps with fogging/freezing up windows. Also trying not to talk a lot helps but that may be hard to control with others in the car.
 
alozzy said:
Hit the front defrost button, which will turn on both the heat and AC buttons. Next, turn off both the heat and AC buttons. Doing that blows fresh air on to the windshield.

Yes, this is what I do most of time, but it still will blow cold air out in the winter, so not something I like to keep continually running while I drive.

This post is just pointing out to new folks that they will very likely need to fiddle more with the heating/cooling system in an EV compared to an ICE, which you usually just can leave on a certain low setting all the time, and not have a lot of fogging/defrost issues.
 
During the time of year when window fogging is a problem: if you're not struggling for range (which hopefully is MOST of the time), leave defrost on. This will minimize the moisure content of the air and fabrics in the cabin. And then should you need to stretch the range for a trip, you won't need as much defrosting.
 
Another option is to use the half fresh/half recycle air function. This is what I do in my Gen 1 Leaf, appears to use the least amount of power and still keep you comfortable during the winter.

Cold Days, turn the air on manually, set fan speed for 1 bar, set the vent direction to floor only, hit the recycle button to close off the vent to the outside. Now after the vent is closed, press and "hold in" the recycle air button until it starts flashing and then let go. This will half open/close the fresh air vent, turn on the heat mode and set the temperature you want (say 70F in winter) and from that point, even though "automatic" climate control is not enabled, it will automatically adjust the air speed (from 1 to 4 bars) to keep the car warm and this will also help to keep the windows from fogging up. It brings in enough fresh air to keep the windows from fogging up, but not enough to use a lot of power trying to warm up tons of "cold" air as it comes in since part of it is recycled inside. :mrgreen:

Best part, it saves these settings between vehicle power on / power off if you don't change them.
 
knightmb said:
Another option is to use the half fresh/half recycle air function. This is what I do in my Gen 1 Leaf, appears to use the least amount of power and still keep you comfortable during the winter.
Or...install Tor's heater mod (for early Gen 1 Leafs) and disable the "heater" function of the defrost cycle. It's a good compromise between draining the battery and (rapidly) defrosting the windows. When you really need to defrost (rapidly), just enable the "heater" function.
 
Stanton said:
knightmb said:
Another option is to use the half fresh/half recycle air function. This is what I do in my Gen 1 Leaf, appears to use the least amount of power and still keep you comfortable during the winter.
Or...install Tor's heater mod (for early Gen 1 Leafs) and disable the "heater" function of the defrost cycle. It's a good compromise between draining the battery and (rapidly) defrosting the windows. When you really need to defrost (rapidly), just enable the "heater" function.

Cool, didn't know it worked for all of them. I only remember it being made for the 2011, 2012 models, at the time, they didn't have anything for the 2013 I was driving, but I guess I should have kept up with it over the years. :mrgreen:
 
Triggerhappy007 said:
Here's the secret to having less foggy windows:

Clean the inside of your windows more often

Very true. The schmutz from off-gassing does haze up at the slightest provocation.
 
knightmb said:
Another option is to use the half fresh/half recycle air function. This is what I do in my Gen 1 Leaf, appears to use the least amount of power and still keep you comfortable during the winter.

Cold Days, turn the air on manually, set fan speed for 1 bar, set the vent direction to floor only, hit the recycle button to close off the vent to the outside. Now after the vent is closed, press and "hold in" the recycle air button until it starts flashing and then let go. This will half open/close the fresh air vent, turn on the heat mode and set the temperature you want (say 70F in winter) and from that point, even though "automatic" climate control is not enabled, it will automatically adjust the air speed (from 1 to 4 bars) to keep the car warm and this will also help to keep the windows from fogging up. It brings in enough fresh air to keep the windows from fogging up, but not enough to use a lot of power trying to warm up tons of "cold" air as it comes in since part of it is recycled inside. :mrgreen:

Best part, it saves these settings between vehicle power on / power off if you don't change them.

Now that's a trick I must have missed along the way. Thanks
 
For anyone looking to buy their first EV: Just note that we've now reached over 1.5 pages of comments on the use of defrosting in an EV. I think that kind of proves my point that it is a bit different in an EV than a "regular" car. Not something you can't overcome (or even THAT big a deal), but just something different you will need to think about sometimes.
 
I think it is probably because when you get used to how the vehicle works, it's just not something to think about until someone brings it up. My family can't still get over the "lack of smell" in an EV. When you ride around in a gas car all the time, you never notice that gas cars, well they smell like gas! Every time I get into a friends vehicle that is gas powered, I can actually smell the car (smells like either gas or oil) and it's odd at first. Of course, they can't smell it or tell the difference, they are use to the smells. Neither could I a decade ago when I was still driving around the gassers' :lol:
 
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