HVAC heating temperature window

[jostafew]

Hello, this is my first vehicle with automatic climate control so I have nothing to compare this behavior to, and I'm wondering if it's by design (for energy conservation) in this case.

It seems that if the outside temp is within about 10 deg of the set interior temp and with the climate controls set to auto, the car just pulls in unheated outside air resulting in a cold cabin. If I bump the temp up a degree or two the heat comes in quick and raises the cabin temp to an uncomfortable level. Set the temp back down to the desired level and it's back to unheated air. However, if the difference between outside air and the HVAC set point is greater than 12 deg it will always heat and the cabin and occupants are comfortable. Less than 10 deg diff and it will pretty much never heat, resulting in cold occupants. This is all with the desired temperature set the same and with the HVAC controls on full auto. The one exception seems to be preconditioning the car, it will consistently heat in that scenario. For reference I'm talking outside temps of 5 - 15 degrees Celsius with a desired cabin temperature of 22deg.

Is this normal behavior? Does the HVAC system in the Bolt have a wider than usual "dead zone" around the set point where it will neither heat nor cool the cabin to conserve energy?

 

[rybolt]

Take a look at the temperature graphs I've posted over in the Technical forum. So far, my experience has been that given enough time at a given setting, the outside air temperature doesn't seem to make much of a difference, just the climate setting. In my Bolt's case, the HVAC consistently pushes hot air at a climate setting of 74º F (or above) and consistently pushes cool air at a climate setting of 70º F (or below).

see: Is HVAC burning you up too? Chevy says "nothing wrong"

 

[phil0909]

Take a look at the temperature graphs I've posted over in the Technical forum. So far, my experience has been that given enough time at a given setting, the outside air temperature doesn't seem to make much of a difference, just the climate setting. In my Bolt's case, the HVAC consistently pushes hot air at a climate setting of 74º F (or above) and consistently pushes cool air at a climate setting of 70º F (or below).

see: Is HVAC burning you up too? Chevy says "nothing wrong"

I have observed similar faulty behavior in my Bolt's climate control, but I had not measured it. Wow - the error is 15 degrees!!! This is definitely not normal, and not satisfactory.

Are all Chevrolet Bolt EVs defective in this regard? Can my Chevrolet dealer repair the defect?

 

[rybolt]

Are all Chevrolet Bolt EVs defective in this regard? Can my Chevrolet dealer repair the defect?

I really want to know the answer to this first question too! So far, I think I might be the only owner to attempt to measure the cabin temperature at various climate control settings. The more folks who can grab a thermometer and test their Bolts, the better idea we'll have as to how widespread this "potential problem" is.

As far as the dealer, I'd definitely recommend demonstrating this to them and allowing them to run whatever tests they can think to run on your vehicle. Even though I haven't had a positive outcome from my own dealer yet, the more people who open a service case, the better the chances are that Chevy will investigate on their end, and I suspect they have much more in the way of resources-- both in Bolts to test and instrumentation with which to measure the results!

 

[jostafew]

Well I feel a little better knowing that others have also found the HVAC temperature control kinda suspect.

I had an extra two probe digital thermometer (from my aquarium actually) that I was using to compare cabin temp to vent temp but it flaked out shortly after I started using it in the car. I guess I'll need to replace it and start making some better notes on the matter.