HVAC Temperature Settings

[mknox]

I think this has been somewhat discussed in other threads, but I wanted to post some observations specifically, and to seek advice as to whether this is something I should have Service look at.

In all my past cars with Auto systems, I have found that setting the temperature at 72 degrees F kept the car comfortable (for me). With my Model S, I have to keep it at 69, and the car is still a wee bit warmer than I'm used to. The fan cycles down so low, that pretty much all the time I have to over-ride the fan speed and turn it up.

Yesterday, after an hour or so drive and with the car still running in my driveway, I snapped the below screen from my smartphone app. You can see it's showing the interior temp at 80 degrees, yet this is after the system has cooled down the car, and "throttled itself back" with the setpoint at 69.

I know newer models have a re-designed cabin sensor with a mechanical aspirator, and maybe that fixes some of what I'm seeing.

Is this "just the way it is" or should I complain to Service that my HVAC isn't working properly?

 

[Monto]

I have the same issue. I find your screen shot interesting. If the car thinks it is 80, why is the fan so low? I don't think the sensor would make any difference in this situation. I wonder what is driving the climate control in this case. I also have complained that the car doesn't ever seem to go in recirculate. Even if the outside temp is in the 90s. My other cars always ramp up, go into recirculate, and then as they cool down, go to outside air.

 

[mknox]

I also have complained that the car doesn't ever seem to go in recirculate. Even if the outside temp is in the 90s. My other cars always ramp up, go into recirculate, and then as they cool down, go to outside air.

Mine does start out in Recirculate, then switches to outside air so it would probably be good to have that checked out. What I've noticed is that the volume of air coming through the vents drops considerably (probably close to half) with the fan at a constant speed when it switches to outside air. I'm wondering if it's a blocked cabin air filter, but it's done that since new.

 

[Monto]

Mine does start out in Recirculate, then switches to outside air so it would probably be good to have that checked out. What I've noticed is that the volume of air coming through the vents drops considerably (probably close to half) with the fan at a constant speed when it switches to outside air. I'm wondering if it's a blocked cabin air filter, but it's done that since new.

How do you know its in recirculate? Mine also drops, but the display seems to always say outside air. I will have to look at it carefully.

 

[Andrew]

I haven't checked what the app is reporting once the car cools off, but I'm constantly having to fiddle with the temperature setting in order to stay comfortable... usually setting it anywhere from 67 to 72.

 

[mknox]

How do you know its in recirculate? Mine also drops, but the display seems to always say outside air. I will have to look at it carefully.

I can hear it. On recirculate, there is a different sound as it draws air in from the cabin (probably under the glove box area) and when it switches to fresh air, I can hear the sound change. This is consistent with how all of my previous vehicles have behaved. I have not actually looked to the display to see what it says.

You could try manually switching between recirculate and fresh air to see if you can hear the difference, then you'll know if it's doing the switch itself in Auto mode.

 

[Monto]

I do hear it, and can replicate it manually, so I guess it is working. My problem is the display. The fan will go from 4 blades solid to 2 solid blades as the fan ramps down. The outside air will not go to the circle mode to indicate recirculate unless I manually change it. My other cars, I can see what the system is doing. Maybe this is just a software problem, but the display should convey what is happening. Same with the ac on/ ac off indication. That should indicate ac off when it is cold enough outside to not need the compressor.

 

[rogelio888]

I haven't checked what the app is reporting once the car cools off, but I'm constantly having to fiddle with the temperature setting in order to stay comfortable... usually setting it anywhere from 67 to 72.

66 for me

 

[fluxemag]

67 for me, same issue where the app says it's around 80 inside the car. There is a huge difference in fan speed between recirculate and not. I have the temperature control on the right scroll wheel because it's basically never where I want it, either blowing too much or not enough. Compare that with my last car where I had the climate control set to 80 and never touched it. This is not to say I'm ever hot and unable to get it cooled down. If I set it to low it's very effective at cooling the car down, especially when I pre-cool it. The car will be around 135 degrees inside after work, and 15 minutes of pre-cooling brings it down to 80 or so.

 

[jerry33]

When I'm not pre-cooling (e.g not plugged in), I start at 25.5 (78 F) and then gradually reduce the temperature. Done this way it's never too hot and is always on outside air.

 

[kendallpb]

72's frequently fine for me. Sometimes I'll dip down to 71 or even 70, but not a lot. Occasionally I'll go up to 73, but usually not. The fan lessens as the car cools off, which is fine for me. I'm not saying it's perfect, but then, I've never liked picking a temperature. The temperature versus how it feels to me and how warm I am (especially if I just got in the car)--and how strong a fan I'd like--can vary a lot.

But usually 71-72 works fine for me.

- - - Updated - - -

When I'm not pre-cooling (e.g not plugged in), I start at 25.5 (78 F) and then gradually reduce the temperature. Done this way it's never too hot and is always on outside air.

I keep A/C on and recirculate on, and the other two settings on auto. Around here, outside air = other cars' exhaust. ;-(

 

[ElectricFarmBoy]

It feels to me like the AC got more "wimpy" after some software update recently. Just today it seemed like it was way warm in the car and yet almost no blower action. I know that wasn't the way it was earlier in the year. So my sense is that something was tweaked in the software and the result isn't as good. So here's hoping it's tweaked back soon....

 

[SCW-Greg]

Mknox, my settings preference and app are just like yours.

Two things,
1) My other/past cars each had their own perfect setting. The Jeep felt best when it said 67. The Avalon felt best at 72/73. Not sure I trusted the newer Avalon, tho you'd think it's supposed to be more accurate.
2) I've heard somewhere on this forum, that the Model S, once temps are close to dialed in, slow the fans down, but also go to a partial recirc mode to help cooling efficiency, rather than full open to outside air (could also explain past defog issues in the Winter). My car does this cycling down noticeably, and I consider this normal operation.

 

[FlasherZ]

"My temperature" in my Suburban is about 2 degrees warmer (70-72) than my temperature in the Tesla (68-70). My kids don't complain about the heat in the third-row, but they come out sweating just a bit after a drive, tinting will likely help with that.

 

[cinergi]

Yes the software for HVAC control does a poor job - I have the same issues and usually just go with manual settings. I've reported it but everyone else here should as well. It's ridiculous that the interior is 80 when set to 60-something.

 

[mknox]

It's ridiculous that the interior is 80 when set to 60-something.

The thing is, I don't think it actuality is 80 in the car, despite what the app says. It's not 69 (my setpoint) either... probably closer to 72 or 73. The system comes on full blast, cools the car down then settles in to a reduced speed. I just find it odd that I have to put the setpoint so low and then to see the app reporting such a high internal temperature. With these inputs I wonder how the software can even figure out what to do.

 

[SCW-Greg]

Yes the software for HVAC control does a poor job - I have the same issues and usually just go with manual settings. I've reported it but everyone else here should as well. It's ridiculous that the interior is 80 when set to 60-something.

Well I'm wondering if there's two different things going on here. One, the temp as stated on the dash, which is fairly close (?) to actual temp... and Two, the temp as reported by the app, which appears to run about 10 degrees higher. At least that's what I'm seeing, and report similar to Mknox.

Edit, looks like Mknox and I are on the same page.

 

[ZBB]

I'm seeing the opposite from you guys...

I kept my prior cars at 68 or 69, and so does my wife. Those include several BMWs (two 3s, an X3 and a 5), a CTS, and a couple Minis.

I keep the Tesla mostly at 71. I've dropped it to 70 or bumped it up to 72 a handful of times...

I've also noticed the app rarely gets below low 80s -- I'm guessing that may be due to the interior temp sensor being below the center arm rest. Makes you wonder if the new part with the small holes above the USB ports helps air flow in there to better report the interior temp?

 

[SCW-Greg]

I'm seeing the opposite from you guys...

I kept my prior cars at 68 or 69, and so does my wife. Those include several BMWs (two 3s, an X3 and a 5), a CTS, and a couple Minis.

I keep the Tesla mostly at 71. I've dropped it to 70 or bumped it up to 72 a handful of times...

I've also noticed the app rarely gets below low 80s -- I'm guessing that may be due to the interior temp sensor being below the center arm rest. Makes you wonder if the new part with the small holes above the USB ports helps air flow in there to better report the interior temp?

In AZ, I'd probably naturally select 72 to 73 for mine too.

FYI, my car does not have this circle of holes above the USB ports. I'm questioning what this really serves. Temp sensors only need a single hole, and in some cases, not even that.

 

[smd]

I usually need to set it to 69-70 to be comfortable. This is about 3 degrees lower than the setting in my Infinitis. I seem to recall that in the wintertime, maybe Jan or Feb 2013, there was a software change when many owners were complaining that the car did not heat up enough. The software was changed (around 4.2?) so that there was more heat produced at each particular temperature setting. That software change could be the reason why at each particular temp the is LESS AC, since that would be a side effect of shifting the temperature response to produce MORE heat at each particular temperature.