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TomT
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Re: Open Windows vs Air Conditioning

Tue May 08, 2012 7:55 am

It really makes no difference. To maintain a given temperature takes a given amount of energy. You will use the same amount of energy overall, either way. You are simply changing the energy loading from front to middle... Even with a given temperature set, you can still override the fan speed and still effectively be in auto by just manually changing the speed. The fan pulls very little, by the way, so it will have no practical difference on the range.
LEAFfan wrote:Someone in another thread posted about the most efficient way to use your A/C. They said to turn on the A/C, turn off 'Auto', lower it to 60, then use just your fan. It works great! So I want to thank them for posting that. After just a few minutes, it shows just a sliver of energy use and the mileage penalty goes to 1 and zero.
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Stanton
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Re: Open Windows vs Air Conditioning

Tue May 08, 2012 8:11 am

adric22 wrote: Personally, I always have the windows down on warm days unless the temperature is over 100 degrees and the sun is shining. At that point I can't take it anymore and have to run the A/C. But I've always been that way, even with gasoline cars. Seems like such a waste of energy.
I take a similar approach, but my pain threshold is more like 80 degrees :o
I like having the windows down (unless I'm on the highway), but I don't like sweating, so I don't over-analyze when it comes to the A/C (now the heat is a different story :oops: )
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Nubo
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Re: Open Windows vs Air Conditioning

Tue May 08, 2012 9:56 am

thejabrother wrote:...the climate control sure does work nicely in these cars!
In an ICE vehicle, the AC condenser is always having a fight with engine heat and the hot radiator that's right next to it. The LEAF's AC lives a life of ease. :)
I noticed you're still working with polymers.

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ksnogas2112
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Re: Open Windows vs Air Conditioning

Tue May 08, 2012 10:59 am

Turn down the a/c in your office so the warm car feels good when you drive home. Unfortunately they turn the a/c on freezer mode here for me so I'm more than happy to get in a warm car to defrost. :lol:
Tom in KS
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defiancecp
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Re: Open Windows vs Air Conditioning

Tue May 08, 2012 11:31 am

TomT wrote:It really makes no difference. To maintain a given temperature takes a given amount of energy. You will use the same amount of energy overall, either way. You are simply changing the energy loading from front to middle... Even with a given temperature set, you can still override the fan speed and still effectively be in auto by just manually changing the speed. The fan pulls very little, by the way, so it will have no practical difference on the range.
While that should be the case, try it and you'll find that - probably due to some minor flaws in software- it is not. When the temp is not set to 60*, the vehicle draws significantly more power at any given time. On the other hand, set it to manual, 60*, and use the fan to regulate temp - you'll notice immediately that it's drawing less power than (for example) setting it to 74* auto, and then you'll find that you end up in low within a few minutes even in very high outside temp/humidity, and once you reach that point climate control power draw will be next to nothing. For that matter until it gets into the upper 90's, I don't bother ever turning the fan up; even on low it cools the interior down fairly effectively in a short period of time.

I don't believe it is the fan that makes the difference; I believe it's two factors-
1) I believe that in auto mode the vehicle uses the heater to a small extent to make the air a specific temperature (ie 70*). This wastes energy in two ways; one, by utilizing the heater, and two, by requiring more cooling effort from the a/c system.
2) the compressor is utilized only as much as needed to maintain an evaporator core temp just above freezing. When the fan is low, the core absorbs less heat from the air, and as a result the compressor is hardly utilized to maintain that temperature. When the fan is high, the compressor is utilized more.

In short, there's a lot of room for software improvement in the way auto mode operates, but in the meantime you can get a much more efficient a/c just by keeping the temp on manual 60 and using the fan to control how much air you use. Before arguing that it shouldn't work, or that you don't think it would be effective, give it a try, you'll be surprised at how little power it uses, and how effective it is at cooling the cabin.

The one down side is that in milder temps the fan just doesn't go low enough... when temps are up to high 80's I find myself having to turn the climate control on and off to regulate temps... Even on the lowest fan setting it will get overly chilly at those temps. Would be nice to have another step in the fan controls that's about 1/2 of the current 'low' setting.


Still, is it more efficient than windows down? Who knows - at high speeds I'd bet on it. At low speeds, I'd bet it's below the point where most people in real roads with real day-to-day variations in conditions would be able to accurately measure the impact of either one.

LEAFfan
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Re: Open Windows vs Air Conditioning

Tue May 08, 2012 12:54 pm

Thanks defiancecp. That was much better than my explanation. I think when Tom tries what we've said, he will realize that it makes a BIG difference. When I had the temp set above 60, I never saw zero or 1 for miles lost so soon. Now, it goes to zero or one really fast and shows just a sliver of energy used.
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GaleHawkins
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Re: Open Windows vs Air Conditioning

Tue Apr 28, 2020 10:17 am

I had been wondering about this since getting the 2016 SL last year. Due to the arthritis I have been a windows guy for years because I was solo most all of the time. Now that most of my driving is taking and picking up my wife from work I run with the windows up more. If on a 95F day I have to set for a while in the car it is so cool to stay cool without running an engine. :)

One thing that got me thinking about an EV last summer was the need for AC when the wife would be late getting off from work. While our ICE options did not over heat coolant wise there was some heat soak into the cabin from the engine and cat. If the car has been setting in the sun in hot weather I still roll down all 4 windows as soon as I can. With the AC on high by the time I get out of the parking lot much of the hot air has escaped so I just close it up.

I finally came up with lithium ion powered hearing aids that I wear all of the time and the windows being down is not so much fun as it was when I could not hear all of the wind noise. :)

gregn
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Re: Open Windows vs Air Conditioning

Sat May 09, 2020 8:52 am

GaleHawkins wrote:
Tue Apr 28, 2020 10:17 am
I had been wondering about this since getting the 2016 SL last year. Due to the arthritis I have been a windows guy for years because I was solo most all of the time. Now that most of my driving is taking and picking up my wife from work I run with the windows up more. If on a 95F day I have to set for a while in the car it is so cool to stay cool without running an engine. :)

One thing that got me thinking about an EV last summer was the need for AC when the wife would be late getting off from work. While our ICE options did not over heat coolant wise there was some heat soak into the cabin from the engine and cat. If the car has been setting in the sun in hot weather I still roll down all 4 windows as soon as I can. With the AC on high by the time I get out of the parking lot much of the hot air has escaped so I just close it up.

I finally came up with lithium ion powered hearing aids that I wear all of the time and the windows being down is not so much fun as it was when I could not hear all of the wind noise. :)
Hi,
EVs have pretty instant climate control response. Also most of them let you precondition the car from a smartphone if you have one. In addition if you have a set time you a planning to leave you can set a timer for the climate control.
Range loss isn't too bad with AC like folks have said once the system gets the bulk of the job done.
I have tested on a highway with windows on AC off and the opposite. I watch the consumption meter and it doesn't change. This is at 65 mph. Seems like it would only have a large effect if the trip was long. The buffeting of the wind in the car might get to you after a while. Personal taste.
As i mention to everyone asking about life with an EV, look at what you normally do in a day of driving. If those miles are less than 80% of a prospective cars EPA range then your inconvenience with charging will be very little. Most folks charge at home overnight. You get to your car in the morning ready for your day.

Greg

I should add that 80% of EPA is just a marker point. If your miles are local at low speeds you will get much more. If it never gets cold where you live that will help too. The range of an EV depends very much on the driving conditions which include type of driving and outside temps and weather. I chose 80% from my experience. It's a bit generous for cold weather.
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LeftieBiker
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Re: Open Windows vs Air Conditioning

Sat May 09, 2020 11:31 am

The car that got many of us interested in buying an EV is the Prius. It too has electric A/C that can be run with the car off (as long as the hybrid battery has enough charge available). The Prius's sluggishness when accelerating also guarantees that most Prius drivers who test drive an EV will find the EV's acceleration to be Awesome - even if it isn't one of the faster ones. So the Prius and similar hybrids prepare people to switch to an EV.
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Re: Open Windows vs Air Conditioning

Wed May 27, 2020 1:57 pm

If you don't want dust in the cabin always keep windows closed.
If you are OK with dust on the dash and everywhere else, keep your windows open up 30mph/50km/h.
Above that start using AC. Short bursts above 35mph do not matter.
Try not to use AC if door is opened every other minute.
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