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AC Noise - Loud!
- Thread starter shonline
- Start date
CHG-ON
Still in love after all these miles
I totally understand the annoyance and the disappointment with spending so much without it being perfect. I knew going in that I was not buying a Merc, etc. I expected some issues. Regarding the AC in particular: no I don't like it. But I have much bigger fish to fry in my life and have decided to not get bent out of shape over it. The car does pretty much everything so damn well.
And it still sounds like a f-ing L1011.
And it still sounds like a f-ing L1011.
bancroftc
Member
Jeff, I have to disagree with you here. I'm in the same boat as TSLA Pilot and find the whole noise/vibration thing extremely annoying and most definitely unacceptable for the class of vehicle we're all driving. That's not being dramatic, it's just an opinion and one that multiple people here seem to agree with. I understand the explanation on why the compressor might be loud, but that doesn't make it ok in a luxury passenger vehicle, electric, ICE or otherwise. And it's not just the noise, the vibration is even worse. I have to believe there is a solution or solutions that can help at least alleviate this.
I realize that there are lots of quirks with the Model S and some we live with, others get addressed. I have a list of items that need to get fixed by Tesla that I've never bothered to mention to anyone or post on forums. It is what it is, as you said. Some I'm sure they can fix and others I'll live with. But when a major vehicle system often sounds and feels like a John Deere riding mower it's time to speak up and not have the concern shrugged off for any number of excuses that have been posted here.
Making excuses for issues like this is a great way for a company to excel at being mediocre and ultimately ruin it's reputation. If Tesla can engineer the best electric vehicle ever made, the doors on Model X, or any other number of mind-boggling design challenges, I'm fairly certain they can come up with a solution to at least hide the noise or dampen the vibration of a technology that's been around for about 100 years.
Thankfully, as I noted previously, Tesla for now seems to be taking my concern seriously and is picking up my car next week to investigate and hopefully fix the issue. So far, I'm pleased they haven't told me to go invent an ultra quiet electrical AC compressor which no one else has invented to date as the solution for my particular issue. I hope you don't work in customer service.
SomeJoe7777
Marginally-Known Member
Engineers don't just throw something together. There are choices to make. I'm an engineer, I do this every day.
The thing is that any engineering you want to do involves trade-offs. Yes, of course, I can make you a compressor that's whisper quiet. I hope, however, you're OK with it sucking down kWh like a vacuum cleaner.
If you want it whisper quiet and energy-efficient, OK, I can do that too. The refrigerant I need for that is $750 / liter and toxic.¹
No solution is going to please everyone. Tesla put an energy-efficient but noisy compressor into the car, you don't like the noise and vibration so you say it's not acceptable. It Tesla were to put in a quiet and inefficient compressor, someone else would be on this forum complaining that sitting in traffic for 30 minutes in the summer uses 10% of the battery, and that's "unacceptable for a $100,000 EV".
Given that range cost (via battery size) is the primary issue holding the Tesla back, the prioritization of energy efficiency over noise seems like a logical choice. When batteries get cheap and range goes up, then I expect there's room to then switch to a less efficient, but quieter compressor.
¹ Hypothetical example.
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bancroftc
Member
I appreciate your commentary (and I'm not disagreeing with you), but if the noise+vibration issue is a known trade-off, then why is Telsa accepting my car into service for this issue? If it's a known issue, why would they not tell me that over the phone and at least attempt to discourage me from having it go to the service center? I guess they could just be doing that to go through the motions, but it seems like a costly an inefficient way to tell people about their loud compressors.
All that said, I'm not convinced that everyone is having this same issue. It seems to be isolated/random as far as I can tell. There is very little commentary about the issue on the forum, and none in my local Tesla group. My buddy owns a shiny new Model X and it does NOT have the same issue as far as I can tell. Yes, probably unfair to compare X to S, but still. This also was not an issue for me for the first few months after I took delivery. So I'm still not convinced that my particular issue has been satisfied. If Tesla comes back next week and tells me that it's 100% normal then I will shut up.
Otherwise all of you naysayers must eat crow
SomeJoe7777
Marginally-Known Member
I think it's good that they are looking at it at the service center for you. Although the compressor design certainly has a noise/vibration that is audible, I would recommend that the service center check yours out to make sure that the noise/vibration isn't excessive, i.e. notably noisier than everyone else's.
It's quite possible that yours may indeed have something wrong with it that is causing the noise level to be way out of line. The only way they can know that is to see it / hear it and compare it to other vehicles.
Ask for a loaner of similar vintage and run it through your analysis. I did the same when I complained about an annoying clunk going over speed bumps. Was told it's normal and did see that the loaner I got made the same exact sound.
I ran my AC on LO and listened to the compressor ramp up to it's max level. I didn't find the noise excessive, just a high pitched but quiet humming coming from the front. Sitting inside, I could barely hear/feel it. 3 month old 85D.
I ran my AC on LO and listened to the compressor ramp up to it's max level. I didn't find the noise excessive, just a high pitched but quiet humming coming from the front. Sitting inside, I could barely hear/feel it. 3 month old 85D.
Well, as the OP, I can say nothing sounds normal on this. Can be heard way down the street. I have a 3 month old model S. It is crazy loud.
However, the service center upon hearing the video I sent, (posted here too) said it was normal and expected. However, videos do not indicate volume like the human ear, so I will have them assess it when I visit for service in a few months.
They offered me a loaner to compare on that visit as well.
Car is awesome and I love it. This sound though, I don't love.
MarkS22
Member
I agree the A/C feels unusually loud. When I give someone a test ride, I turn off the A/C because you can't otherwise appreciate the quiet motor. Even on 1 it adds a dramatically louder sound. When you turn it off while stopped, the cabin feels silent. On a recently built Model S, I think the perception of loud A/C is partially due to signal to noise ratio. There's no engine running, so it stands out more.
Using a Sound Level Meter dB(A) on a P85D:
Off: 28.0dB (virtually silent)
A/C 1/Lowest: 44.9dB (quiet living room)
A/C 5/Middle: 55.2dB (quiet car at low speeds)
A/C 11/Max: 69.4dB (moderately loud)
These are all "A-weighted" to attempt to standardize to the human ear's response. I used SPLnFFT on an iPhone 6S as well as a Radio Shack analog meter for sounds over 60dB. (0 dB would be a perfect hearing threshold for a young male, but "normal" goes to 15dB. The older you are, the more likely your hearing threshold is much higher.)
Now, the A/C 1 and A/C 5 levels (44-55dB) on the Model S are actually pretty low... about the same as an average quiet home. (My office, with two computer fans blowing a few feet away, is 37db.) A normal conversation is between 55-65db. The difference between 55db and 29db, however, is quite dramatic if you do an on/off comparison.
If you crank it to 11, well, nearly 70db is moderately loud. Like vacuum cleaner loud. It's enough to start overpowering a "normal conversation."
By comparison, I tested a 2016 Mercedes GLC 300, built two months ago. This is a newly refreshed model, so I thought it would be a good comparison. It also has Eco Start/Stop, but (to be clear) the engine started up when the A/C came on. I pulled the GLC out of the garage on a quiet street, so the engine noise wouldn't be amplified inside:
Using a Sound Level Meter dB(A) on GLC 300:
Off: 29.8dB (almost identical to Model S)
A/C 1/Lowest: 41.5dB (less than Tesla by 3.4dB)
A/C 3/Middle: 42.5db* (less than Tesla by 12.7dB)
A/C 7/Max: 70.5dB (almost identical to Model S, within 1dB)
*It only goes from 1-7 as opposed to 1-11, so I used 3 as a halfway, but it felt slower than the Model S's halfway, while 4 seemed too strong.
Now, I know this isn't an S-class, but the objective numbers show very close sound levels from the A/C on a 2016 C-Class Mercedes. Indeed, the Off and Max are nearly identical, within 1dB (and margin of error). Even the 1st AC level is within 3dB. To be honest, I perceived the Mercedes to have quieter A/C and expected lower numbers. It makes me wonder how much the lack of all other noise is making the Tesla seem louder.
It's also possible the "middle" level 5 (on the Model S) and the level 3 (on the GLC) are what's most often used to keep the cabin comfortable. And, if that's the case, there's 12.7dB of additional A/C sound on the part of the Model S. That could be influencing the perception.
I think Tesla is trying to address this A/C sound on the 3 by making the vent one long slit instead of multiple vents. You can have the same amount of air being blown into the cabin without the noise of the air. This, with a quieter compressor, could have a significant effect on the audio levels. I'd imagine some of these design features will be incorporated into the S/X.
Using a Sound Level Meter dB(A) on a P85D:
Off: 28.0dB (virtually silent)
A/C 1/Lowest: 44.9dB (quiet living room)
A/C 5/Middle: 55.2dB (quiet car at low speeds)
A/C 11/Max: 69.4dB (moderately loud)
These are all "A-weighted" to attempt to standardize to the human ear's response. I used SPLnFFT on an iPhone 6S as well as a Radio Shack analog meter for sounds over 60dB. (0 dB would be a perfect hearing threshold for a young male, but "normal" goes to 15dB. The older you are, the more likely your hearing threshold is much higher.)
Now, the A/C 1 and A/C 5 levels (44-55dB) on the Model S are actually pretty low... about the same as an average quiet home. (My office, with two computer fans blowing a few feet away, is 37db.) A normal conversation is between 55-65db. The difference between 55db and 29db, however, is quite dramatic if you do an on/off comparison.
If you crank it to 11, well, nearly 70db is moderately loud. Like vacuum cleaner loud. It's enough to start overpowering a "normal conversation."
By comparison, I tested a 2016 Mercedes GLC 300, built two months ago. This is a newly refreshed model, so I thought it would be a good comparison. It also has Eco Start/Stop, but (to be clear) the engine started up when the A/C came on. I pulled the GLC out of the garage on a quiet street, so the engine noise wouldn't be amplified inside:
Using a Sound Level Meter dB(A) on GLC 300:
Off: 29.8dB (almost identical to Model S)
A/C 1/Lowest: 41.5dB (less than Tesla by 3.4dB)
A/C 3/Middle: 42.5db* (less than Tesla by 12.7dB)
A/C 7/Max: 70.5dB (almost identical to Model S, within 1dB)
*It only goes from 1-7 as opposed to 1-11, so I used 3 as a halfway, but it felt slower than the Model S's halfway, while 4 seemed too strong.
Now, I know this isn't an S-class, but the objective numbers show very close sound levels from the A/C on a 2016 C-Class Mercedes. Indeed, the Off and Max are nearly identical, within 1dB (and margin of error). Even the 1st AC level is within 3dB. To be honest, I perceived the Mercedes to have quieter A/C and expected lower numbers. It makes me wonder how much the lack of all other noise is making the Tesla seem louder.
It's also possible the "middle" level 5 (on the Model S) and the level 3 (on the GLC) are what's most often used to keep the cabin comfortable. And, if that's the case, there's 12.7dB of additional A/C sound on the part of the Model S. That could be influencing the perception.
I think Tesla is trying to address this A/C sound on the 3 by making the vent one long slit instead of multiple vents. You can have the same amount of air being blown into the cabin without the noise of the air. This, with a quieter compressor, could have a significant effect on the audio levels. I'd imagine some of these design features will be incorporated into the S/X.
Took a video of my car with max AC. Hard to tell if it's any different than your video. Hope it helps.
It would be helpful to know what the temperature was when you made these recordings, and whether the battery might already have been hot from being used, or if the car had been just sitting in the garage for an extended period.
I just heard what is probably the same sounds in my 2015 S for the first time. We had a 95F day here on Saturday -- extremely hot for our area, and humid. My car had been parked in the sun without moving for 2 or 3 hours, and it is a fairly dark color (multicoat red), so the interior temp was well over 100F when i needed to go out. I started the AC remotely using the phone app, a few minutes before I left. When I came out of the building, I heard the car, but at first did not realize it was my car. It sounded as if someone might be running a vacuum cleaner, perhaps to clean a car in a nearby garage. Not until I got closer to my car did I realize it was my car! To me, it sounded mainly like fan noise, and did not surprise me because of the extreme heat. The noise was reduced rapidly as the cabin cooled, and as I got the car moving.
Notably, the energy consumption that day was about the same as it was on the coldest winter days -- up in the 500 Wh/mile range. (But my trips were short.)
Yours sounds smoother than the OP's. On his, I almost think I am hearing a fan blade, either loose and vibrating or as if it is hitting something...
Yep. That is the grinding noise as I describe it. But normal according to the service center team.
It was in the 80's. The car had not been driven at all in one of the videos. Very slightly in the other.
Fan noise I can live with. The metal sound from the compressor is the one that sounds far too loud.
bancroftc
Member
I appreciate your commentary (and I'm not disagreeing with you), but if the noise+vibration issue is a known trade-off, then why is Telsa accepting my car into service for this issue? If it's a known issue, why would they not tell me that over the phone and at least attempt to discourage me from having it go to the service center? I guess they could just be doing that to go through the motions, but it seems like a costly an inefficient way to tell people about their loud compressors.
All that said, I'm not convinced that everyone is having this same issue. It seems to be isolated/random as far as I can tell. There is very little commentary about the issue on the forum, and none in my local Tesla group. My buddy owns a shiny new Model X and it does NOT have the same issue as far as I can tell. Yes, probably unfair to compare X to S, but still. This also was not an issue for me for the first few months after I took delivery. So I'm still not convinced that my particular issue has been satisfied. If Tesla comes back next week and tells me that it's 100% normal then I will shut up.
Otherwise all of you naysayers must eat crow
So I guess it's my turn to eat crow - got my car back from Tesla on Friday and they are saying that everything related to my AC noise complaints is totally normal and within design tolerances. So go ahead and dish it out...BUT that doesn't mean that I've changed my stance on the matter. I'll agree that it is what it is. It was engineered that way - fine. But "what it is" is still quite annoying and could use a lot of refinement IMO. So perhaps they were just going through the motions with the hope of shutting me up. They did fix a number of other rattles and squeaks while it was in the shop so that was much appreciated.
I'll let it go, but it's still frustrating. Our second car is a 2015 Yukon Denali which from the outside, is as loud as one would expect a 6.2L V8 engine to be. But from the inside it is SIGNIFICANTLY quieter with AC at full blast both at a standstill and at full highway speeds. No vibrations or anything like that from the AC system. Just the noise of air coming out of the vents. Quieter all the way around actually, meaning the combination of engine noise + AC noise is quieter than my Tesla with just the AC on high. Totally different cars, I get it - but despite the massive/loud engine and all the AC wizardry needed to cool a much larger cabin, our Yukon is much, MUCH quieter than my Tesla in the cabin. It does have active noise canceling technology in the cabin, so that probably has a lot to do with it (maybe something Tesla could benefit from).
Anyways...moving on.
Model S M.D.
Ludicrous Radiologist
Mine is at the SC right now for dual chargers, steering rack creak and to check out my AC noise as well. I suspect they will tell me its normal. This is my first summer with the Model S and it gets pretty hot down here in Texas, so maybe it really is "normal." Its pretty embarrassing when my "silent" car makes a whole ton of noise when its hot outside...
You can eliminate the noise (except when Supercharging) by starting the A/C with the temperature high (27 or so). This will still feel cooler than outside, and you dial it down as the cabin cools.
I turn mine on when I'm in parking lots as a noise maker so that pedestrians don't get caught off guard
Model S M.D.
Ludicrous Radiologist
Just got my car back from the SC for dual chargers, steering rack creak bulletin fix, and AC noise. Here is the official word from them regarding my complain of loud AC:
"Performed function testing of AC system. Noted vehicle is operating as designed, consistent with other known good Model S vehicles.
Customer should note that as ambient temperatures increase, the demand load of the A/C system is taxed heavily, especially in high humidity climates. As a result, slightly higher audible outputs from system will be noted. This is a normal operating condition."
I was also told that a recent firmware update increased the power draw from our AC units due to multiple customer complaints that the AC wasn't cold enough, which also contributes to a louder noise...
Anyway, it was nice that they topped off my washer fluid, tire pressure and performed a general courtesy inspection along with washing my car.
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