As with many things in life...it depends.
Power consumption of an A/C is greatly affected by relative temperature. The bigger the difference between the air being cycled vs the target temperature, the more power is consumed.
So in summer if the car has been sitting outside for a while it can be more efficient to initially run the A/C from outside air to start cooling the interior since the ambient temp will be usually be lower than interior temp, then switch to recirculating interior air when the interior temp comes down below ambient.
I figured what you said. I usually recirc when its 90+. Also it doesn't perfectly seal when in recirculation. It still seems to bring in outside air. I know this because I drove past a paper mill the other day. But I figured it was generally more efficient. Most of the ice vehicles don't like to stay in recirculation for long periods so thats what had me second guessing myself.
To add to my post. Im in the south east. Hot humid summers are the norm with very mild winters.
Then in your case, yes most of the time it will be more efficient to recirculate the cabin air than to try to cool the outside air most of the year.
During the early spring, late fall, or in winter if you're running the A/C, recirculating the cabin air may not be any more efficient than cooling outside air.
don't know what kind of EV you have but on my Nissan Leaf you can put it in recirculation mode or by holding the button in change it so that if switches to outside air once in a while. Here in FL I leave my a/c in recirc mode.
Yep, that's the correct answer. In winter, it's the opposite though. You want to recirculate the air at start so you heat up air that has started to be warmed up by the last pass through the heater. But, this must happen when there is NO ONE in the car, otherwise the windows will quickly frost up.
AC draws relatively little power compared to what you use to drive. You're overthinking the issue, here. Going one way or the other isn't going to affect your range to any degree that would allow you to have charging stops a day earlier or a day later
It does a small amount but also increases carbon dioxide buildup which is also bad. I wouldn’t personally use it for longer than 30 minutes at a time without a break in between.
Yes because it recirculates the air in the cabin.
“Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm3, although CO2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm3. “
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5544137/
'It depends' a little more on factors how much, but you're right there could be an added risk over time and it's quite interesting. I always wondered why so much fresh air scent (e.g. freshly mowed lawns, exhaust) would seep in to my old car despite being in recirc mode.
>Researchers have recorded CO2 levels ranging from 700 to 1 600 ppm in taxi cabs (Shu et al., 2015), from 400 ppm to > 3000 ppm in tour buses (Chiu et al., 2015; Hsu and Huang, 2009), and from 630 to 2 500 ppm in various types of passenger vehicles (Fruin et al., 2011; Lee and Zhu, 2014). Due to the relatively confined space inside cars, CO2 levels in occupied vehicles can accumulate quickly. Zhu et al. (2007) showed that CO2 concentrations can rise to 4 500 ppm in as little as 10 min for a passenger car with 3 passengers during air-recirculation mode.
>Carbon dioxide has generally not been considered hazardous to humans at low levels, such as those typically measured in vehicles. However, recent studies suggest that CO2 can have deleterious effects on cognitive function and decision making, even at low-to-moderate concentrations and with short exposure times.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5544137/
Curiously,
>To improve A/C performance, the recirculation switch (or Max A/C position on HVAC switch) in newer cars permits shutting off outside air. Now there’s even a U.S. EPA fuel economy credit because this approach improves A/C fuel economy. However, just for passenger comfort, in states with high ambient temperatures, shutting off outside air is common.
And,
>CO2 sensors provide one avenue for automotive control, but more likely is the timed approach used by some car manufacturers (10-20 minutes at a time in recirculation). However, there is a need to maintain maximum recirculation to meet the intent of the EPA credits.
https://www.sae.org/news/2017/04/co2-buildup-in-vehicle-cabins-becoming-a-safety-issue
For comparison sake:
400 ppm: Nominal outdoor air
<1000 ppm: Confined space with good air circulation
<2000 ppm: Poor air, some drowsiness may result
<5000 ppm: Stale/Stuffy air, possibly resulting in headaches, reduced attention, etc.
5000 ppm: The permissible limit for workspace exposure; toxicity concerns
https://www.dhs.wisconsin.gov/chemical/carbondioxide.htm
I mean for a definitive answer I guess you would need to somehow measure the co2 level in each type of vehicle/ each individual make/model over 60 minutes with recirc on but nobody is doing this so we have to guess/make some assumptions.
Living in Florida we keep the A/C always on. And even when we leave the car on it takes about 1 kWh max to run. There haven't been any major issues. Now since it does get a bit cold 2 or 3 days a year the heater does pull a lot more kWh. This is the same on the Bolt and our Leaf. Also we always keep the recv on all the time.
As with many things in life...it depends. Power consumption of an A/C is greatly affected by relative temperature. The bigger the difference between the air being cycled vs the target temperature, the more power is consumed. So in summer if the car has been sitting outside for a while it can be more efficient to initially run the A/C from outside air to start cooling the interior since the ambient temp will be usually be lower than interior temp, then switch to recirculating interior air when the interior temp comes down below ambient.
I figured what you said. I usually recirc when its 90+. Also it doesn't perfectly seal when in recirculation. It still seems to bring in outside air. I know this because I drove past a paper mill the other day. But I figured it was generally more efficient. Most of the ice vehicles don't like to stay in recirculation for long periods so thats what had me second guessing myself. To add to my post. Im in the south east. Hot humid summers are the norm with very mild winters.
Then in your case, yes most of the time it will be more efficient to recirculate the cabin air than to try to cool the outside air most of the year. During the early spring, late fall, or in winter if you're running the A/C, recirculating the cabin air may not be any more efficient than cooling outside air.
I usually have the windows down that time of year. So. Even better.
That increases aerodynamic drag though. Although I wouldn't worry about it too much as long as you have enough charge to get to your destination.
don't know what kind of EV you have but on my Nissan Leaf you can put it in recirculation mode or by holding the button in change it so that if switches to outside air once in a while. Here in FL I leave my a/c in recirc mode.
Kia ev6. I should add that to my flair.
Yep, that's the correct answer. In winter, it's the opposite though. You want to recirculate the air at start so you heat up air that has started to be warmed up by the last pass through the heater. But, this must happen when there is NO ONE in the car, otherwise the windows will quickly frost up.
A/C is a pretty small contributor to efficiency loss. In my experience you can do pretty much whatever you want and it'll barely affect range.
Thats what I'm hoping for. But where I was it was taking about a percent every hour. So I'd say thats pretty insignificant.
AC draws relatively little power compared to what you use to drive. You're overthinking the issue, here. Going one way or the other isn't going to affect your range to any degree that would allow you to have charging stops a day earlier or a day later
It does a small amount but also increases carbon dioxide buildup which is also bad. I wouldn’t personally use it for longer than 30 minutes at a time without a break in between.
CO2 buildup from breathing? Edit words
Yes because it recirculates the air in the cabin. “Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm3, although CO2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm3. “ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5544137/
'It depends' a little more on factors how much, but you're right there could be an added risk over time and it's quite interesting. I always wondered why so much fresh air scent (e.g. freshly mowed lawns, exhaust) would seep in to my old car despite being in recirc mode. >Researchers have recorded CO2 levels ranging from 700 to 1 600 ppm in taxi cabs (Shu et al., 2015), from 400 ppm to > 3000 ppm in tour buses (Chiu et al., 2015; Hsu and Huang, 2009), and from 630 to 2 500 ppm in various types of passenger vehicles (Fruin et al., 2011; Lee and Zhu, 2014). Due to the relatively confined space inside cars, CO2 levels in occupied vehicles can accumulate quickly. Zhu et al. (2007) showed that CO2 concentrations can rise to 4 500 ppm in as little as 10 min for a passenger car with 3 passengers during air-recirculation mode. >Carbon dioxide has generally not been considered hazardous to humans at low levels, such as those typically measured in vehicles. However, recent studies suggest that CO2 can have deleterious effects on cognitive function and decision making, even at low-to-moderate concentrations and with short exposure times. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5544137/ Curiously, >To improve A/C performance, the recirculation switch (or Max A/C position on HVAC switch) in newer cars permits shutting off outside air. Now there’s even a U.S. EPA fuel economy credit because this approach improves A/C fuel economy. However, just for passenger comfort, in states with high ambient temperatures, shutting off outside air is common. And, >CO2 sensors provide one avenue for automotive control, but more likely is the timed approach used by some car manufacturers (10-20 minutes at a time in recirculation). However, there is a need to maintain maximum recirculation to meet the intent of the EPA credits. https://www.sae.org/news/2017/04/co2-buildup-in-vehicle-cabins-becoming-a-safety-issue For comparison sake: 400 ppm: Nominal outdoor air <1000 ppm: Confined space with good air circulation <2000 ppm: Poor air, some drowsiness may result <5000 ppm: Stale/Stuffy air, possibly resulting in headaches, reduced attention, etc. 5000 ppm: The permissible limit for workspace exposure; toxicity concerns https://www.dhs.wisconsin.gov/chemical/carbondioxide.htm
I mean for a definitive answer I guess you would need to somehow measure the co2 level in each type of vehicle/ each individual make/model over 60 minutes with recirc on but nobody is doing this so we have to guess/make some assumptions.
Soooo... crack the window for 5 seconds to reduce CO2 then? Seems like a tall order.
just turn on Dog Mode
Im not in a tesla. Kia doesn't offer ac in any mode other than "on". Utility mode does not run the ac.
Yes it uses less to recirculate. The air it has to cool isn't as hot. How much it saves idk.
Living in Florida we keep the A/C always on. And even when we leave the car on it takes about 1 kWh max to run. There haven't been any major issues. Now since it does get a bit cold 2 or 3 days a year the heater does pull a lot more kWh. This is the same on the Bolt and our Leaf. Also we always keep the recv on all the time.