Impact of AC

Impact of AC

Hey folks:

Looking to pull the trigger on a Model S and trying the 60kWh vs 85kWh version. The one question I have is what is the impact of AC on range--lots of 90+ days during the summer. What is the impact of AC on range with these kinds of temps?



andex23 | 12 juin 2013

Hi Omar,

My experience is that range is barely effected by AC usage. I did two long trips (600 miles round trip each) with a P85. The first one I put the electonics in range mode, which modifies the performance of the AC. Temps were between 55 and 80. The second trip I left range mode off and let the conditoner do its thing at 71 degres for the entire trip. temperatures were slightly higeher on average on the second trip so the airconditioner was working more/harder. There was no noticeable difference. Ultimately, I determined that I will not be using "range mode" on long trips. The absolute biggest factor in my eletricity usage is speed as it relates to wind drag. If you want to drive fast often and hate being behind someone (very useful for drafting even without tailgating) then upgrade to the 85kwh, otherwise, AC is minimal.

Actually, I just swapped out from loaner 19s to my due bill 21s and THAT makes a much larger difference in energy consumption than the AC.

Rod and Barbara | 12 juin 2013

@ Omar - According to the range calculator on the Tesla website at Go Electric > Your Questions Answered > How Far Can I Go, there is a 3% loss of range at 65 MPH and 9% loss of range at 45 MPH between 70 deg F, AC off and 90 deg F, AC on. Note, that the affect of AC only is greater than that. The loss of range between 90 deg F, AC off and 90 deg F, AC on, is 6% at 65 MPH and 11% at 45 MPH.

Carefree | 12 juin 2013

I live in blazing hot Arizona - we hit 110F today! The impact of the AC on range is far less than I ever anticipated. Much less than the impact the heater has. I hardly notice a reduction of range caused by the AC.

Theresa | 12 juin 2013

Andes, approximately how much difference do the 21s make in range?

stevenmaifert | 12 juin 2013

Omar - My experience has been that headwinds have a far greater impact on range than A/C use.

wthieldelgado | 12 juin 2013

Just did a trip from SF Bay Area to Vegas. AC usage had very little effect on energy usage, even in the 100-108 degree heat. If I didn't know the AC was on for hundreds of miles, I wouldn't have noticed, as my wh/mile numbers were the same as my overall average.

andex23 | 12 juin 2013

Hi Theresa, I posted on another thread(think its private) but the difference so far is ~7% or so with about 400 miles on the new wheels. I was getting 308 wh/mi with the 19s over 2k miles and now am averaging as of tonight 328wh/mi over the last 400 on the 21s. Not a big difference but I notice it substantially more than the AC! Again, speed will be the largest energy sync.

DouglasR | 12 juin 2013

There was speculation in another thread that the use of accessories like AC might not actually be reflected in the watt-hours/mile (whpm) numbers on the trip meter. That is, just as the trip meter does not show vampire load when the car is stationary, perhaps it shows only consumption from the power train and not the accessories when the car is moving. The use of accessories would of course be reflected in the drop in rated miles, but not in the trip meter's whpm display.

If anyone is in a position to test this theory, I would be interested in your observations. Just do your commute both with and without AC and other accessories, and compare the whpm. Thanks.

Brian H | 13 juin 2013

Yeah, check the change in miles and do your own arithmetic and see if it jibes.

Trekker56 | 13 juin 2013

Salams Omar, have a 60kWh in Virginia which gets pretty hot too. Not noticeable AC impact in day-to-day driving. On long range (100 miles+ highway trips), switch to range mode which puts the AC on Eco mode and again no noticeable impact.

mpottinger | 13 juin 2013

My experience in the Denver area: A/C has minimal impact; cold weather has a significant impact. As for the cold weather impact, I'm not sure if it is cabin heat or battery heat that causes the most draw.

Joshua Burstyn | 13 juin 2013


"There was speculation in another thread that the use of accessories like AC might not actually be reflected in the watt-hours/mile (whpm) numbers on the trip meter."

I'd agree but the heater definitely drives the dials up on the energy side of the speedometer. (Very much so, actually. Having the defroster on high makes a big difference, actually.)

cgiGuy | 13 juin 2013

I've also noticed the sliver of orange on the power meter while parked with my AC on full blast. | 13 juin 2013

Thanks folks for all the responses.


fluxemag | 13 juin 2013

I also live in AZ. I pre-cool the car for about 20 minutes twice a day before I go down to the parking lot. Going from 140 interior temp to 80 eats up about 3 miles of rated range. So running the AC on max for an hour is less than 10 miles range in my experience in the hottest possible temps. While driving it appears to be a pretty low impact, but can't say for sure because it has always been on since I got the car a few weeks ago.

DouglasR | 13 juin 2013

@Jewsh - Yes, I know that accessory use shows on the energy side of the speedometer. However, I'm interested in the trip meter, both the kWh used and the average whpm since the last charge. The trip meter numbers derive from the same base: that is, whpm is always kWh used/miles traveled. Since the trip meter registers no energy usage while the car is stationary (e.g., vampire load), I am wondering whether it simply excludes accessory use and measures only usage from the drive train.

I will try it myself, but as I don't have a daily commute, it is less convenient. I will have to set up a test drive of enough length to make the comparison meaningful, and then drive it several times to measure the difference in kWh used with and without accessories.

swhardy | 13 juin 2013

Go to and enter a common route you'll be driving, and set the Cabin and Ext Temps to the same value, such as 73, for both. Note what the Total and Average Energy values are. Next increase the Ext Temp value to whatever your high temp would be and see what the difference is in your Energy values.

I did this for my 35 mile round trip from home to work. With no AC (both Temps at 73) my Total Energy was 9.7 kWh (278 Wh/mile). With Ext Temp set to 115 (not uncommon in AZ) the numbers were 11.7 kWh (334 Wh/mile). I was told by the show room guys to figure on a 10% drop in range from heavy AC use but these numbers equate to 20%.