Defrost / Defog: Just want fan

[mknmike]

I was driving today in the 34 F sunny day and the car full of 5 needed no heat. We were comfortable like cattle in a barn warming it up ourselves, but of course we needed to defog the windshield. I didn’t want to let the heat pump run, and would really like to be able to just run the blower (directed at the windshield). Is this possible?

Thanks!
Mike

 

[Sophias_dad]

I believe one press of the 'defog' icon will make it blue(no heat), the second will make it red(heat).

 

[mknmike]

I believe one press of the 'defog' icon will make it blue(no heat), the second will make it red(heat).

Yes. Blue appears to be no heat, but does it run the AC? It does turn on the temp number as if I turned on the climate control.

Then the next annoying thing is not having a single button to turn off the hvac. Swipe up and then turn off is what I do repeatedly now.

 

[Alan_F]

Yes. Blue appears to be no heat, but does it run the AC? It does turn on the temp number as if I turned on the climate control.

Then the next annoying thing is not having a single button to turn off the hvac. Swipe up and then turn off is what I do repeatedly now.

Long press on the temperature to turn climate off if you want to do it without bringing up all the controls.

 

[RayK]

Yes. Blue appears to be no heat, but does it run the AC? It does turn on the temp number as if I turned on the climate control.

Then the next annoying thing is not having a single button to turn off the hvac. Swipe up and then turn off is what I do repeatedly now.

Running the AC is the most effective (note that I didn't say efficient) way to defrost a windshield.

 

[mknmike]

Long press on the temperature to turn climate off if you want to do it without bringing up all the controls.

Thank you! This is news to me. I certainly will try this next time I’m in the car.

So now if I could just learn how to manually control the various HVAC controls, I’d have everything. I wonder why Tesla doesn’t seem to offer the functionality. I guess if could probably all be fixed with a software update if there’s not already a way.

 

[Benito1283]

Thank you! This is news to me. I certainly will try this next time I’m in the car.

So now if I could just learn how to manually control the various HVAC controls, I’d have everything. I wonder why Tesla doesn’t seem to offer the functionality. I guess if could probably all be fixed with a software update if there’s not already a way.

The manual climate controls are pretty self explanatory. I used to futz with manual a lot but I find Auto works perfectly and takes all the guesswork out.

FYI, the AC is the most critical part of defogging since it’s what dehumidifies the air. If you’re too warm, lower the temp.

 

[jdw]

You can get fan only by turning off auto, setting the temperaure to a low setting and turning off AC.

 

[Big Earl]

Thank you! This is news to me. I certainly will try this next time I’m in the car.

So now if I could just learn how to manually control the various HVAC controls, I’d have everything. I wonder why Tesla doesn’t seem to offer the functionality. I guess if could probably all be fixed with a software update if there’s not already a way.

There are lots of threads about micromanaging the climate control. They usually result in discomfort, dissatisfaction with dehumidification performance (fogging) or both.

Automatic mode will prevent fogging while keeping the cabin at a comfortable temperature and humidity.

You can do just air to the windshield by selecting the windshield vents, setting a manual fan speed, deselecting AC and setting the temperature to LO. This will do fan only. With five people, you’ll probably need a fan speed of at least 4.

 

[Stew-2]

I always figured (perhaps wrongly so) that the heat pump was always running in some capacity or another whether or not I’m directing heat or AC into the cabin.

How many valve positions does the octovalve have to move heat around from motors, batteries, cabin, ??? Lots for it to do other than cabin temperature.

 

[fholbert]

I was driving today in the 34 F sunny day and the car full of 5 needed no heat. We were comfortable like cattle in a barn warming it up ourselves, but of course we needed to defog the windshield. I didn’t want to let the heat pump run, and would really like to be able to just run the blower (directed at the windshield). Is this possible?

Thanks!
Mike

To effectively defog the windshield, especially with 5 on board, you need the heat pump to dry the air. Just set the temperature at a neutral setting.

No need to make something simple, hard.

 

[mknmike]

I always figured (perhaps wrongly so) that the heat pump was always running in some capacity or another whether or not I’m directing heat or AC into the cabin.

How many valve positions does the octovalve have to move heat around from motors, batteries, cabin, ??? Lots for it to do other than cabin temperature.

I have been assuming that when I hear the loud vibrating thing in the front of the car, that’s the heat pump compressor. Compressors are the things in homes that take the most power. So I assume in cars it’s the same (other than propulsion). So I’d like to extend range and be as efficient as possible. If fresh cool outside air is enough to clear the windshield in an ICE vehicle, I don’t see why it would t be enough in a EV. I do understand that heated air is easy to come by in an ICE vehicle, but when the cabin is so toasty warm without heat, I’d think cool air would still do it. Cracking my driver window was clearing it up, but it much noisier than running an HVAC fan with fresh outside air.

It seems this is a scenario where they tried to dumb it down more than I’d prefer requiring the heat pump / AC to be running any time you want to blow cabin air around, and maybe they decide for you whether you need heat pump or AC.

If that’s the case, and they decide for you if you need heat pump / AC, then I’d think that if you match the desired temp to the actual temp, perhaps THEN you’d be able to run the fan without heat pump or AC. I know you can view the cabin temp on the phone app. So maybe that’s the trick. Find cabin temp (on the phone app) and set the temp to that. Any other ideas?

 

[Foxsbiscuits]

I have been assuming that when I hear the loud vibrating thing in the front of the car, that’s the heat pump compressor. Compressors are the things in homes that take the most power. So I assume in cars it’s the same (other than propulsion). So I’d like to extend range and be as efficient as possible. If fresh cool outside air is enough to clear the windshield in an ICE vehicle, I don’t see why it would t be enough in a EV. I do understand that heated air is easy to come by in an ICE vehicle, but when the cabin is so toasty warm without heat, I’d think cool air would still do it. Cracking my driver window was clearing it up, but it much noisier than running an HVAC fan with fresh outside air.

It seems this is a scenario where they tried to dumb it down more than I’d prefer requiring the heat pump / AC to be running any time you want to blow cabin air around, and maybe they decide for you whether you need heat pump or AC.

If that’s the case, and they decide for you if you need heat pump / AC, then I’d think that if you match the desired temp to the actual temp, perhaps THEN you’d be able to run the fan without heat pump or AC. I know you can view the cabin temp on the phone app. So maybe that’s the trick. Find cabin temp (on the phone app) and set the temp to that. Any other ideas?

If you're after efficiency don't open your windows! Creates drag

 

[Big Earl]

Any other ideas?

I explained how to do fan-only in my post above.

 

[mknmike]

I explained how to do fan-only in my post above.

Thanks. I think I missed this:
“You can do just air to the windshield by selecting the windshield vents, setting a manual fan speed, deselecting AC and setting the temperature to LO. This will do fan only. With five people, you’ll probably need a fan speed of at least 4”

 

[Big Earl]

I got my steps a little out of order. Select LO temp then turn off AC.

 

[mknmike]

I explained how to do fan-only in my post above.

I got my steps a little out of order. Select LO temp then turn off AC.

Tried this this morning, and it seems to work pretty well to almost instantly clear the windshield. I think the fan running at just level 1 might be perfect (with one kid in the car getting shuttles to school).

There are a lot of clicks to get here. I think it went like this:
- defrost button (in my frequently used)
- temp to low (if not already there)
- swipe up temp for full controls
- turn off the AUTO
- turn off AC
- turn fan way down from the level 7-8 wherever it was. Level 4 was clearing it real fast. Probably need to try level 1.

Then if if gets too cold and I want to shut it off…
- hold my finger on the temp

When fog comes back, repeat the cycle. Since there’s so many clicks in the first step, I think finding the ideal fan speed for continuous low level defog would be ideal. I probably need to let the fan run a few seconds on 4 and drop it to 1. I will see if I can try that tomorrow morning when dropping off the kids.

Having the ability to set a shortcut or macro to do the above steps would be nice. The car is a big computer. So I bet there’s a way.

 

[Foxsbiscuits]

If all of this is to save energy I don't think it's worth it from either a practical perspective or an energy saving one. You'll be constantly fiddling with the controls and screen for like a 1% difference.

I used to want to always turn off AC for a similar reason, now I just set temp and trust auto. It regularly runs auto defog and I've never had an issue. Change of mindset around AC.

 

[Big Earl]

Tried this this morning, and it seems to work pretty well to almost instantly clear the windshield. I think the fan running at just level 1 might be perfect (with one kid in the car getting shuttles to school).

There are a lot of clicks to get here. I think it went like this:
- defrost button (in my frequently used)
- temp to low (if not already there)
- swipe up temp for full controls
- turn off the AUTO
- turn off AC
- turn fan way down from the level 7-8 wherever it was. Level 4 was clearing it real fast. Probably need to try level 1.

Then if if gets too cold and I want to shut it off…
- hold my finger on the temp

When fog comes back, repeat the cycle. Since there’s so many clicks in the first step, I think finding the ideal fan speed for continuous low level defog would be ideal. I probably need to let the fan run a few seconds on 4 and drop it to 1. I will see if I can try that tomorrow morning when dropping off the kids.

Having the ability to set a shortcut or macro to do the above steps would be nice. The car is a big computer. So I bet there’s a way.

I can’t imagine jumping through all of these hoops to save a few cents worth of electricity.

But here we are, so I’ll continue offering suggestions. Instead of clicking the windshield defrost button, click the windshield vent button. This will not set the fan to 7-8 like the defrost button does, saving you some steps. It will also remember this configuration when you toggle climate control off and on.

 

[mknmike]

I can’t imagine jumping through all of these hoops to save a few cents worth of electricity.

But here we are, so I’ll continue offering suggestions. Instead of clicking the windshield defrost button, click the windshield vent button. This will not set the fan to 7-8 like the defrost button does, saving you some steps. It will also remember this configuration when you toggle climate control off and on.

Thank you. I need to learn where that button is. I will try to search when driving my son to basketball practice tonight. Thank you for the spoon feeding. I really appreciate it.