Feature Request - Eco-Mode Air Conditioning

[Sam T]

Ok guys, I’ve done a tonne of research and have discovered my AC unit is defective. Similar issues have been well documented where the AC blows warm intermittently, or not warm at all. Seems like the most common fix is to replace between 1 and 3 sensors on the system.

My apologies, since my car is brand new, roadside assistance and the service centre couldn’t find the fault, I assumed all was ok. Must be just difficult to diagnose.

Sorry again.

Still, a heater button would help with comfort.

You say it’s efficient, ok I believe you, but my unit uses somewhere around 5-10 times as much energy as my friends with the same model, year, settings and location. Also my compressor turns off at least once a minute.

 

[DownshiftDre]

Go into Service Mode and watch the heat pump do its thing. And compare to your friends. There are also a couple of performance tests you can run in service mode. And keep bugging the service center.

 

[Sam T]

Good advice I’ll do that thanks

 

[Sam T]

 

[Supcom]

Much has changed in the three years since that video was created.

 

[Sam T]

What has changed?

 

[Supcom]

What has changed?

Model Y is no longer the only Tesla with a heat pump.

 

[JulienW]

Model Y is no longer the only Tesla with a heat pump.

All have heat pumps now (assuming the Semi does too).

All Tesla Vehicles Now Have Efficiency-Boosting Heat Pump

After giving the refreshed Model S and Model X a heat pump, Tesla gave all its vehicles this component to improve their energy efficiency on cold days.

insideevs.com

 

[derotam]

Ok guys, I’ve done a tonne of research and have discovered my AC unit is defective. Similar issues have been well documented where the AC blows warm intermittently, or not warm at all. Seems like the most common fix is to replace between 1 and 3 sensors on the system.

My apologies, since my car is brand new, roadside assistance and the service centre couldn’t find the fault, I assumed all was ok. Must be just difficult to diagnose.

Sorry again.

Still, a heater button would help with comfort.

You say it’s efficient, ok I believe you, but my unit uses somewhere around 5-10 times as much energy as my friends with the same model, year, settings and location. Also my compressor turns off at least once a minute.

So the service center has fixed the problem? Great!

 

[beachmiles]

Many Tesla's do not have a heat pump and instead have a PTC cabin heater that gets constantly used when you only want to cool the car. I don't want to send 300-1000 constant wasted watts to my cabin heater in my battery powered car when I only want to cool the car. This has been a 4+ year issue across all Tesla models without a heat pump. Being forced to leave my temp setting at LO and throttling the AC button manually to control the cabin temp is the only way to get the car to not use the cabin heater when it's 80F outside. This is completely batshit insane and absolutely terrible HVAC coding with no hysteresis and a plain waste of power. Please give us a dedicated heater off button and/or 2 temp setpoints like a home HVAC.

Here are threads talking about the heat coming on when only cooling is desired

cabin heater coming on when only cooling desired

teslamotorsclub.com

Here are threads talking asking for a heater off button / 2 temp setpoints.

ac 2 temperature setpoints

teslamotorsclub.com

 

[UncleCreepy]

This has been a 4+ year issue across all Tesla models without a heat pump.

This thread is about a feature request and therefore refers to future models (all current models already haave heat pumps), unless you are expecting Tesla to retrofit older models.

 

[derotam]

Many Tesla's do not have a heat pump and instead have a PTC cabin heater that gets constantly used when you only want to cool the car. I don't want to send 300-1000 constant wasted watts to my cabin heater in my battery powered car when I only want to cool the car. This has been a 4+ year issue across all Tesla models without a heat pump. Being forced to leave my temp setting at LO and throttling the AC button manually to control the cabin temp is the only way to get the car to not use the cabin heater when it's 80F outside. This is completely batshit insane and absolutely terrible HVAC coding with no hysteresis and a plain waste of power. Please give us a dedicated heater off button and/or 2 temp setpoints like a home HVAC.

Here are threads talking about the heat coming on when only cooling is desired

cabin heater coming on when only cooling desired

teslamotorsclub.com

Here are threads talking asking for a heater off button / 2 temp setpoints.

ac 2 temperature setpoints

teslamotorsclub.com

If you have your setpoint at 72 when it is 80 degrees out, I'm pretty sure the PTC heater does NOT turn on. I could be wrong of course but I think if you have a wide enough setpoint differential the heater will not be on constantly. Actually, I KNOW that for a fact, it's just a matter of what differential is required. Once warmer temps come in I can look at that again in my 2018 LR RWD.

 

[beachmiles]

This thread is about a feature request and therefore refers to future models (all current models already haave heat pumps), unless you are expecting Tesla to retrofit older models.

This is a software feature request for all tesla models but is especially relevant to model years before 2022 that don't have heat pumps. Many of these cars are still under factory warranty and share the same HVAC hardware as models out of warranty. Why in the heck wouldn't you push a simple software update to add a heater off button. Slightly more difficult but better would be adding 2 temperature setpoints like your home thermostat. A digital display of a nest thermostat would be freaking amazing.

One of the selling points of Tesla is that features are always added via software updates and the HVAC controls could use some many missing features and especially bug fixes like the HVAC code has been riddled with for years.

 

[derotam]

Many Tesla's do not have a heat pump and instead have a PTC cabin heater that gets constantly used when you only want to cool the car. I don't want to send 300-1000 constant wasted watts to my cabin heater in my battery powered car when I only want to cool the car. This has been a 4+ year issue across all Tesla models without a heat pump. Being forced to leave my temp setting at LO and throttling the AC button manually to control the cabin temp is the only way to get the car to not use the cabin heater when it's 80F outside. This is completely batshit insane and absolutely terrible HVAC coding with no hysteresis and a plain waste of power. Please give us a dedicated heater off button and/or 2 temp setpoints like a home HVAC.

Here are threads talking about the heat coming on when only cooling is desired

cabin heater coming on when only cooling desired

teslamotorsclub.com

Here are threads talking asking for a heater off button / 2 temp setpoints.

ac 2 temperature setpoints

teslamotorsclub.com

You can disagree with me all you want, you have data to prove that the heater ALWAYS comes on and stays on CONSTANTLY? I've already looked at data as of a couple months ago using SMT with my OBDII adapter, specifically watching the heater power as I turned down the temp setpoint. The PTC heater is NOT CONSTANTLY on.

I DO however agree that it does turn on in some circumstances when it does not need to be on and the broadness of circumstances are not trivial.

EDIT: let me put my hedge in here, there could be a possibility that Tesla has changed the behavior since I last collected data. I normally try to reserve my above comments after I get current data but I am 99.9% sure I am right here. Data to be collected tonight and summarized tomorrow.

 

[derotam]

This is a software feature request for all tesla models but is especially relevant to model years before 2022 that don't have heat pumps. Many of these cars are still under factory warranty and share the same HVAC hardware as models out of warranty. Why in the heck wouldn't you push a simple software update to add a heater off button. Slightly more difficult but better would be adding 2 temperature setpoints like your home thermostat. A digital display of a nest thermostat would be freaking amazing.

One of the selling points of Tesla is that features are always added via software updates and the HVAC controls could use some many missing features and especially bug fixes like the HVAC code has been riddled with for years.

They have fixed a LOT with the HVAC over the years via updates. It uses to be that, ironically enough given our conversation, that the heat would NOT turn on with a set point below I think it was 63 or 65. I documented that issue in the past as well....again with in vehicle CAN bus data.

 

[beachmiles]

If you have your setpoint at 72 when it is 80 degrees out, I'm pretty sure the PTC heater does NOT turn on. I could be wrong of course but I think if you have a wide enough setpoint differential the heater will not be on constantly. Actually, I KNOW that for a fact, it's just a matter of what differential is required. Once warmer temps come in I can look at that again in my 2018 LR RWD.

My Tesla service center verified the cabin heater gets used all the time when only cooling is desired in 2019 and said they expect it to be fixed in software. 3 years later and the the bug still exists.

You can use a DC current clamp sensor on the PTC cabin heater power line or use the OBD/CAN adapter with the scanmytesla app to verify yourself. You will use less power setting the temp to LO instead of 72F when it's 80F outside and you will also see this in the car hvac power usage chart.
This is and has been happening for years.

 

[beachmiles]

You can disagree with me all you want, you have data to prove that the heater ALWAYS comes on and stays on CONSTANTLY? I've already looked at data as of a couple months ago using SMT with my OBDII adapter, specifically watching the heater power as I turned down the temp setpoint. The PTC heater is NOT CONSTANTLY on.

I DO however agree that it does turn on in some circumstances when it does not need to be on and the broadness of circumstances are not trivial.

EDIT: let me put my hedge in here, there could be a possibility that Tesla has changed the behavior since I last collected data. I normally try to reserve my above comments after I get current data but I am 99.9% sure I am right here. Data to be collected tonight and summarized tomorrow.

My Tesla service center verified the cabin heater gets used all the time when only cooling is desired in 2019 and said they expect it to be fixed in software. 3 years later and the the bug still exists.

You can use a DC current clamp sensor on the PTC cabin heater power line or use the OBD/CAN adapter with the scanmytesla app to verify yourself. You will use less power setting the temp to LO instead of 72F when it's 80F outside and you will also see this in the car hvac power usage chart.

I've tested almost every build with the scanmytesla app for years verifying the same behavior. I haven't done a test in a couple months so maybe they have magically fixed it in a 2024 build. I'm still on a 2023 fsd branch.

 

[derotam]

My Tesla service center verified the cabin heater gets used all the time when only cooling is desired in 2019 and said they expect it to be fixed in software. 3 years later and the the bug still exists.

You can use a DC current clamp sensor on the PTC cabin heater power line or use the OBD/CAN adapter with the scanmytesla app to verify yourself. You will use less power setting the temp to LO instead of 72F when it's 80F outside and you will also see this in the car hvac power usage chart.

I've tested almost every build with the scanmytesla app for years verifying the same behavior. I haven't done a test in a couple months so maybe they have magically fixed it in a 2024 build. I'm still on a 2023 fsd branch.

Forgive me being a bit nitpicky here with the video but I am working off your statement of absolute constant on behavior... Multiple times it was shown that the PTC heater was drawing 0W for multiple seconds, one count was 15 seconds. Also I will note that a setpoint of 72 with and outside temp of 80 is not sufficient of a differential and given that in the video it was showing the PTC left/right going between 77W, 155W, 233W and 0W shows that you are close to the edge of the required differential. I would venture to say that if the temp setpoint was 68, that the PTC wouldn't not be on.

I'll also mention that in the video the person stated they pulled the power connector to the PTC heater and had the setpoint at 80 degrees and the HVAC still ran and got the cabin temperature into the 60's... Are you/they trying to imply that the setpoint in just AC mode does nothing and that the AC is ALWAYS ON and it is just the fan speed and PTC heating that is controlling the cabin temp?

***this paragraph corrected in the next paragraph but left in for reference. Further I will note that at one point the display showed 83degrees outside, the Tesla app showing Exterior at 75 degrees, and the car was in the shade. That would possibly indicate a temperature sensor problem, which could cause HVAC issues. Additionally the HVAC was still in the auto mode set to 72 degrees and the interior cabin on the app was showing 78 degrees and the SMT data was showing cabin was at 83 degrees.

***Correcting last paragraph(which makes your arguement worse)...Video person found error with Tesla App data and corrected it. Then shows Interior 73 degrees, Exterior matching vehicle display and SMT data of 82-83 degrees. With a setpoint of 72 degrees it shows even more that the temperature differential isn't enough to keep the PTC off. Additionally when the person changed the set point to 73 degrees they lamented at the PTC heater jumping to ~1200W...With an interior temp of 73 degrees, and a set point of 73 degrees, of course the PTC heater was going to kick on. The person left it this way for over 5 minutes! This just showed normal and proper heat usage.

I stopped watching at ~24 minutes because the testing metholodgy was just horrible and the person is biased toward his opinion and got stuck in a narrow window of parameters that seemed to show what he wanted to show(I don't believe they did this on purpose however). At 23-24 minutes they dropped the temp to 70 degrees and the PTC heater went to 0W, they waited a few seconds(PTC never turned on) and put it right back to 73 degrees where the PTC STILL stayed at 0W for 48 seconds before starting to twitch between 77W and 0W at ~24:20 in the video. Again with a set point of 73 and a cabin temp of 73, what do you expect?

Testing methodology here was horrendeous. If this was your video, re-run the test and look at it with setpoints all the way down to 62 degrees(before it switches to LO).

Edit: I just skimmed the rest of the 50 minute video and the person kept the HVAC setpoint at 73 degrees with no further variations in test parameters. This was not a good testing scenario.

 

[beachmiles]

Forgive me being a bit nitpicky here with the video but I am working off your statement of absolute constant on behavior... Multiple times it was shown that the PTC heater was drawing 0W for multiple seconds, one count was 15 seconds. Also I will note that a setpoint of 72 with and outside temp of 80 is not sufficient of a differential and given that in the video it was showing the PTC left/right going between 77W, 155W, 233W and 0W shows that you are close to the edge of the required differential. I would venture to say that if the temp setpoint was 68, that the PTC wouldn't not be on.

I'll also mention that in the video the person stated they pulled the power connector to the PTC heater and had the setpoint at 80 degrees and the HVAC still ran and got the cabin temperature into the 60's... Are you/they trying to imply that the setpoint in just AC mode does nothing and that the AC is ALWAYS ON and it is just the fan speed and PTC heating that is controlling the cabin temp?

***this paragraph corrected in the next paragraph but left in for reference. Further I will note that at one point the display showed 83degrees outside, the Tesla app showing Exterior at 75 degrees, and the car was in the shade. That would possibly indicate a temperature sensor problem, which could cause HVAC issues. Additionally the HVAC was still in the auto mode set to 72 degrees and the interior cabin on the app was showing 78 degrees and the SMT data was showing cabin was at 83 degrees.

***Correcting last paragraph(which makes your arguement worse)...Video person found error with Tesla App data and corrected it. Then shows Interior 73 degrees, Exterior matching vehicle display and SMT data of 82-83 degrees. With a setpoint of 72 degrees it shows even more that the temperature differential isn't enough to keep the PTC off. Additionally when the person changed the set point to 73 degrees they lamented at the PTC heater jumping to ~1200W...With an interior temp of 73 degrees, and a set point of 73 degrees, of course the PTC heater was going to kick on. The person left it this way for over 5 minutes! This just showed normal and proper heat usage.

I stopped watching at ~24 minutes because the testing metholodgy was just horrible and the person is biased toward his opinion and got stuck in a narrow window of parameters that seemed to show what he wanted to show(I don't believe they did this on purpose however). At 23-24 minutes they dropped the temp to 70 degrees and the PTC heater went to 0W, they waited a few seconds(PTC never turned on) and put it right back to 73 degrees where the PTC STILL stayed at 0W for 48 seconds before starting to twitch between 77W and 0W at ~24:20 in the video. Again with a set point of 73 and a cabin temp of 73, what do you expect?

Testing methodology here was horrendeous. If this was your video, re-run the test and look at it with setpoints all the way down to 62 degrees(before it switches to LO).

Edit: I just skimmed the rest of the 50 minute video and the person kept the HVAC setpoint at 73 degrees with no further variations in test parameters. This was not a good testing scenario.

I agree the test scenarios were not clearly presented like the manual vs auto HVAC mode tests and dropping the temp to verify the current sensor also would read 0.
When changing the temp on the car there is a ramp rate where the cabin heater will try to stay off but as a steady state temp forms so does the cabin heater staying on 98% of the time.
At 24:40 the cabin heater starts getting close to steady state on above 300 watts.

I will try to make another video with clearer test conditions with clearer results but there has only been a few cases I've seen where the cabin heater is not used when only cooling is desired and thats during a couple short drives when it's 90F plus outside. When the outside temp is just a few degrees above your temp setpoint seems to be the worst case where the cabin heater is used even more.

Others like Josh Wardell who made the model 3 can dbc file verified this behavior as well. Will dig up his post.

GitHub - joshwardell/model3dbc: DBC file for Tesla Model 3 CAN messages

DBC file for Tesla Model 3 CAN messages. Contribute to joshwardell/model3dbc development by creating an account on GitHub.

github.com

Turns out it was a private message. This is what he wrote, also attached the graph of his can output showing the cabin heater use.
"So here's a new shot of the same run, and I added cabin humidity as well, though that doesn't seem to really be affected (I guess you could say that shows things working).
The heaters quickly spike to 2kW each but quickly stabilized at about 800W each. But I would prefer to repeat the test for a longer time to see what the heater use averages. Of course it won't be warm enough for another 6-7 months"

So I know it's not just me. Please run a can test with your test setup if you could.

 

[derotam]

I agree the test scenarios were not clearly presented like the manual vs auto HVAC mode tests and dropping the temp to verify the current sensor also would read 0.
When changing the temp on the car there is a ramp rate where the cabin heater will try to stay off but as a steady state temp forms so does the cabin heater staying on 98% of the time.
At 24:40 the cabin heater starts getting close to steady state on above 300 watts.

I will try to make another video with clearer test conditions with clearer results but there has only been a few cases I've seen where the cabin heater is not used when only cooling is desired and thats during a couple short drives when it's 90F plus outside. When the outside temp is just a few degrees above your temp setpoint seems to be the worst case where the cabin heater is used even more.

Others like Josh Wardell who made the model 3 can dbc file verified this behavior as well. Will dig up his post.

GitHub - joshwardell/model3dbc: DBC file for Tesla Model 3 CAN messages

DBC file for Tesla Model 3 CAN messages. Contribute to joshwardell/model3dbc development by creating an account on GitHub.

github.com

Turns out it was a private message. This is what he wrote, also attached the graph of his can output showing the cabin heater use.
"So here's a new shot of the same run, and I added cabin humidity as well, though that doesn't seem to really be affected (I guess you could say that shows things working).
The heaters quickly spike to 2kW each but quickly stabilized at about 800W each. But I would prefer to repeat the test for a longer time to see what the heater use averages. Of course it won't be warm enough for another 6-7 months"

So I know it's not just me. Please run a can test with your test setup if you could.

Let's be clear here about what your opinion is first because I don't want to get caught in a moving goal post scenario which you just kind of did I think unknowingly. You have made very opinionated statements which is fine but from a testing standpoint we need to get a set theory down to be able to test against. I am working of your below statement:

Many Tesla's do not have a heat pump and instead have a PTC cabin heater that gets constantly used when you only want to cool the car. I don't want to send 300-1000 constant wasted watts to my cabin heater in my battery powered car when I only want to cool the car.

There is technical issue with the statement but I am interpreting pretty strictly, based on other comments you have made, that you are saying PTC cabin heater is "constantly" used when in ANY AC cooling scenario. Let me stop there and see where you are standing. I ONLY got into this discussion with you because of your insistence that the PTC heater is CONSTANTLY on which I do not agree with.

I don't have a problem in testing against and politely DISCUSSING a clearly defined theory. I also don't have a problem arguing against emotionally charged statements, but those are two completely different paths of conversation. I have done both on this forum and others.