Air condition vs windows open

Air condition vs windows open

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Do you conserve energy by opening windows and turning off AC? I did various tests and here are the results (spoiler alert):

100 km/h, 62 mph:
AC on, windows up: 211 Wh/km, 340 Wh/mi
AC off, windows up: 201 Wh/km, 324 Wh/mi
HVAC off, windows open: 204 Wh/km, 328 Wh/mi

70 km/h, 43 mph:
AC on, windows up: 161 Wh/km, 259 Wh/mi
AC off, windows up: 153 Wh/km, 246 Wh/mi
HVAC off, windows open: 151 Wh/km, 243 Wh/mi

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Når det er så varmt som nå, så synes jeg det beste er å kjøre med alle sidevinduene nede til ca 50 km/t. Mellom 50 og 80 er det greit å lukke igjen bakvinduene, over 80 lukker jeg vinduene og setter på AC.
P.S. Jeg kjører bensin, så jeg bryr meg ikke om rekkevidde… 😉

I found a very fast way to cool down a hot car, is to start driving with the passenger's window down and the window behind the driver down with other windows up. The diagonal air flow sweeps hot air from the back out. Then I roll up and use the AC.

Windows down and the interior of the car will look like crap after a short while. I'd rather drive with AC off and fan speed up to avoid all the dust from entering the car 😊 But, it was an interesting test.

I love every single one of your videos. You always do such good videos, and awesome tests. I've been subscribed for a long time now and I'm always excited to see your videos. Your Channel has grown so much since I first subbed

I see a lot of people opening two windows on the same side for various reasons. I open one front and one opposite rear window just enough to stop the drumming while allowing the desired flow. I leave the driver’s window closed if it is sun side. Rarely have to use the A/C unless the temperature is 90+f (32c).

Since you did a HVAC video. I am curious on its “special features”. I have a 2006 Cadillac CTS with dual climate control. I leave it in auto nearly year round. With a slight temp change here and there.

The auto function is the best I’ve came across. There is a sensor in the middle of the dash that senses light level and direction of the sun. Say both the driver and passenger had the temp setting at 70°F. And I’m driving with the sun beating down on me. Well the HVAC will know this from the sensor in the dash and will vent out 68° to me and 70-71° to the passenger. It’s attempting to keep mother driver and passenger at 70°.

It also determines how bright the sun is and it’s frequency. Where my house is and the road, I have a lot of trees that cover the car. So it’s pretty cool to start off on a summer’s day. But when I drive onto a road that has no trees. The sensor picks that up and ramps up the fan speed automatically to keep up with the sun beating down.

Also during cold weather, close to and below freezing. It will automatically blow the air at the windshield. But at a few minute delay to allow the engine’s coolant to heat up.

I am curious, how does a Tesla handle this in automatic mode?

On Mythbusters they had huge temperature difference with AC. He was wearing a jacket and it was blasting on full. This is why the consuption was so big then.

Tesla had it on their website that opening the windows vs AC is less efficient. I believe they assumed having the windows all the way down. Hot is also relative. Here in Los Angeles, hot is 30-40 Celsius. I feel very sorry for people with some old car that don't have AC (or it's broken). Driving at 120 km/h with the windows open at 35 C is just silly. Air pollution here is also pretty bad so you really don't want to have the windows down.

if ya open window all way down both side and back hatch open so it blow heat out back so wont stay in car and i drive my truck everyday with back window open and both side window feel much better than AC

The best is to open two windows on the same side of the car about 10-15cm. And if driving alone in the car, open the windows on the passenger side (opposite of the driver), that way the draft is on the driver.

What I do is I open both windows on the opposite side – this gives me less noise and swirl of cold air comes directly from behind to cool me down 🙂 on my ICE cat I use AC few times a year as too big ambient temperature differences can lead to health problems (sore throat, sinuses pain).

If you use the windows, you'd better use them in one side (front+rear). The windnoise lower, and the wind spin around inside. You'll feel this moving air not only near your upper body but around yourl legs.
He wind arrives from the rear window, leave from the front.

Great info. Thanks for setting my expectations for this summer. I wonder however if you have the same weather conditions again if you can do one more test. Drive whatever speed in this test again with
a/c pump off, fan at middle or higher and windows up, but this time with a/c in seats running. The kWh for just the seats I think you told us before is very low compared to pump and might be more effective than cracking window open…..

Definitely a great test to perform. As with many things on an electric car, AC has a much different energy consumption effect than on an ICE car. Since the engine is already turning, and at high speed, it's already turning in a higher powered way than at low speed, the AC can create a far less important drag on an ICE car's engine.

I'm glad you tested the middle condition of windows up, air circulating with fan too, because in the end, that's how we should generally be driving on freeways, unless it's sweltering out. That is true of ICE cars too. And efficiency matters in EV driving, not just to extend range, but because an electron saved, is an electron earned. Thanks for your test!

You really can't go above about 30mph comfortably with the windows wide open. The popping and noise will give you a headache quickly.

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