It appears that when you set a cabin temperature, the vehicle will run either A/C or heat to maintain that temperature. On the other hand, my house thermostat lets me set a temperature range so that the A/C runs only when the house is warmer than the upper end of the range, and it runs heat only when the house is below the lower end of the range.. When the house temperature is inside of the temperature range, nothing runs, thereby saving electricity. Why doesn't Tesla apply this simple concept to their vehicles?
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Cabin Temperature Range
- Thread starter Family Joules
- Start date
E90alex
Active Member
The cabin temperature of a car increases very rapidly in the sun and is a much smaller area almost completely surrounded by glass. Even without sun the cabin can get very humid and stuffy quickly just from breathing and body heat, especially with more than one person.
Nothing like a house with 4-6 inch insulated walls, with dual pane windows here and there and blinds/curtains.
But the cars HVAC system is variable and will ramp up/down and cycle as needed to maintain temperature. It’s not a simple binary on and off and just because the system is blowing air doesn’t mean the compressor is running. You just usually can’t tell in the car when it cycles.
Nothing like a house with 4-6 inch insulated walls, with dual pane windows here and there and blinds/curtains.
But the cars HVAC system is variable and will ramp up/down and cycle as needed to maintain temperature. It’s not a simple binary on and off and just because the system is blowing air doesn’t mean the compressor is running. You just usually can’t tell in the car when it cycles.
On nice days, when the inside of the car gets a little warm from sunlight coming through the windows, I run climate on fan only with no AC.
RTPEV
Active Member
What you are looking for is a dead zone, and I agree, it is a relatively simple change that can and should be done in code, albeit at the expense of a more complicated UI (which is probably why it hasn't been done).
This topic has been covered quite extensively on the forum, and I wasn't going to further add to the discussion, but @E90alex brought up a slightly different point than what I've seen before in this thread. At certain times of the year (spring and fall mainly, at least in those areas that have more seasonal climates), the outdoor temperature will still be quite hot in the afternoon, so you have have your HVAC set at say 72 (for example -- obviously everyone's comfort level is different). When you go out to your car in the morning, the outdoor air temperature (and cold soaked cabin) may be a brisk 60 or so, but still within the comfort range of the occupant. Ideally you would just want outside air. But no, the car senses the temperature difference between the set point of 72 and the cabin at 60 and blasts the heat, which is definitely not wanted. So you have to set the temperature down to a very low value to avoid hot air blowing in your face...maybe 65 will do it because of the effect that @E90alex mentioned (small cabin and warm body occupant). Then after your comfortable commute, you get of the car for a day's work and come out in the afternoon where maybe now it's in the high 80's or low 90's (in my area anyway), and 65 is WAY too low a temperature. Not only is it unnecessary for comfort, but it requires the fan to run extremely high to try to keep up with the high outside temperature (for the very reasons that @E90alex listed: not a ton of insulation, double paned glass and blinds), so you adjust the thermostat back up to 72 or whatever your comfort level is, until you get home. Rinse and repeat until the outdoor temperature reaches a point where it's either already warm enough in the morning to warrant AC or cold enough in the afternoon to warrant heat.
Fortunately this is only for a few weeks every year, but yes, like my home thermostat that has three modes: heat, cool, and heat/cool with a programmable dead zone, it would be nice for the car to have something similar. And I believe some do. And before we had all these newfangled HVAC systems, even old cars had this feature:
The VENT setting is basically what we are talking about, and it was a simple movement of the knob (or button press) to enable it. Now we have to jump through menus and temperature adjustments to achieve basically what @dusty22 does.
This topic has been covered quite extensively on the forum, and I wasn't going to further add to the discussion, but @E90alex brought up a slightly different point than what I've seen before in this thread. At certain times of the year (spring and fall mainly, at least in those areas that have more seasonal climates), the outdoor temperature will still be quite hot in the afternoon, so you have have your HVAC set at say 72 (for example -- obviously everyone's comfort level is different). When you go out to your car in the morning, the outdoor air temperature (and cold soaked cabin) may be a brisk 60 or so, but still within the comfort range of the occupant. Ideally you would just want outside air. But no, the car senses the temperature difference between the set point of 72 and the cabin at 60 and blasts the heat, which is definitely not wanted. So you have to set the temperature down to a very low value to avoid hot air blowing in your face...maybe 65 will do it because of the effect that @E90alex mentioned (small cabin and warm body occupant). Then after your comfortable commute, you get of the car for a day's work and come out in the afternoon where maybe now it's in the high 80's or low 90's (in my area anyway), and 65 is WAY too low a temperature. Not only is it unnecessary for comfort, but it requires the fan to run extremely high to try to keep up with the high outside temperature (for the very reasons that @E90alex listed: not a ton of insulation, double paned glass and blinds), so you adjust the thermostat back up to 72 or whatever your comfort level is, until you get home. Rinse and repeat until the outdoor temperature reaches a point where it's either already warm enough in the morning to warrant AC or cold enough in the afternoon to warrant heat.
Fortunately this is only for a few weeks every year, but yes, like my home thermostat that has three modes: heat, cool, and heat/cool with a programmable dead zone, it would be nice for the car to have something similar. And I believe some do. And before we had all these newfangled HVAC systems, even old cars had this feature:
The VENT setting is basically what we are talking about, and it was a simple movement of the knob (or button press) to enable it. Now we have to jump through menus and temperature adjustments to achieve basically what @dusty22 does.
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