HEPA Filter replacement schedule?

[NSCyber]

How often do these normally need to be replaced?

Drove through an evacuation zone today due to a fire and even with bio defense mode activated you could smell the fire inside the car. Thought that it eliminated 99.9% of odors?

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[thrillbourne]

Per the service manual:

HEPA filter replacement every 2 years, or every year in cases of off-road/dirt road driving or excessive pollution

Last summer I drove through the Gorman wildfires, engaged BDM early on and thought it did a great job filtering out the smoke. I did start to smell it after about 10-15 minutes though.

 

[Vegetaban]

Probably need to replace when going through that type of stuff.

 

[HaulingAss]

How often do these normally need to be replaced?

Drove through an evacuation zone today due to a fire and even with bio defense mode activated you could smell the fire inside the car. Thought that it eliminated 99.9% of odors?

Haha! That would be a real trick if it could eliminate 99.9% of the odors! It's mostly a HEPA particulate filter. It can remove virus and dust, and some odor, but not odor from combustion gases to any degree. To do that you would need pounds and pounds of carbon or other absorbent media and it would have to be replaced frequently.

Even so, a HEPA filter is a huge benefit to remove particulates, allergens and infectous organisms, even if some smells come through. It will be most effective on odors if you keep the fan speed low. That will reduce the velocity of the intake air through the filter media.

If you were willing to replace the big filter every month, you would get more odor reduction but not 99.9% and that's just not very practical for most people. I like that I can keep the interior nearly dust free simply by keeping the windows up whenever I'm in traffic or dry, dusty conditions.

I think the official schedule is to replace it every 2 years unless in dusty conditions, then every year or as needed. In very dusty areas with a lot of hours of use I could see replacing it every 3 months. But where I live in the damp PNW my Tesla filters easily go two years.

Common sense says replacement interval has to do with how hard you run the fan too. The more air you pump through the filter, the sooner it should be replaced. That said, the Cybertruck is the first vehicle I've owned that has an "upside down" HEPA filter. That means larger particles wont plug the filter up, they will fall back down into the air intake, which could extend your filter life depending upon what is getting drawn into your air intake. My Model 3 HEPA filters are far smaller and get filled with needles, insects, twigs and dry leaf crumbles (because they are not "upside-down").

 

[igs]

How often do these normally need to be replaced?

Drove through an evacuation zone today due to a fire and even with bio defense mode activated you could smell the fire inside the car. Thought that it eliminated 99.9% of odors?

Bio defense mode just sucks in even more outside air. Best to turn off the ac or run in recirculate mode.

 

[NSCyber]

Haha! That would be a real trick if it could eliminate 99.9% of the odors! It's mostly a HEPA particulate filter. It can remove virus and dust, and some odor, but not odor from combustion gases to any degree. To do that you would need pounds and pounds of carbon or other absorbent media and it would have to be replaced frequently.

Even so, a HEPA filter is a huge benefit to remove particulates, allergens and infectous organisms, even if some smells come through. It will be most effective on odors if you keep the fan speed low. That will reduce the velocity of the intake air through the filter media.

If you were willing to replace the big filter every month, you would get more odor reduction but not 99.9% and that's just not very practical for most people. I like that I can keep the interior nearly dust free simply by keeping the windows up whenever I'm in traffic or dry, dusty conditions.

I think the official schedule is to replace it every 2 years unless in dusty conditions, then every year or as needed. In very dusty areas with a lot of hours of use I could see replacing it every 3 months. But where I live in the damp PNW my Tesla filters easily go two years.

Common sense says replacement interval has to do with how hard you run the fan too. The more air you pump through the filter, the sooner it should be replaced. That said, the Cybertruck is the first vehicle I've owned that has an "upside down" HEPA filter. That means larger particles wont plug the filter up, they will fall back down into the air intake, which could extend your filter life depending upon what is getting drawn into your air intake. My Model 3 HEPA filters are far smaller and get filled with needles, insects, twigs and dry leaf crumbles (because they are not "upside-down").

I noticed every time I turn it on it’s on full blast.

 

[NSCyber]

Bio defense mode just sucks in even more outside air. Best to turn off the ac or run in recirculate mode.

Best to keep it off or in recirculate mode vs biodefense?

 

[igs]

Best to keep it off or in articulate mode vs biodefense?

Yes it is full blast sucking in outside air.

 

[CyberGus]

“The HEPA filter ensures the best quality air inside the cabin whenever the climate control system is on and outside air is entering the cabin (recirculate is off). The HEPA filter is extremely effective at removing particles, including pollution, allergens, bacteria, pollen, mold spores, and viruses. When you engage Bioweapon Defense Mode, the positive pressure inside the cabin minimizes the amount of outside air that can enter the vehicle.

Note
Some gases, such as carbon monoxide, are not effectively removed by activated carbon.”

https://www.tesla.com/ownersmanual/cybertruck/en_us/GUID-CFA216A5-F2CC-416F-97E8-8560E0CC4161.html

 

[NSCyber]

“The HEPA filter ensures the best quality air inside the cabin whenever the climate control system is on and outside air is entering the cabin (recirculate is off). The HEPA filter is extremely effective at removing particles, including pollution, allergens, bacteria, pollen, mold spores, and viruses. When you engage Bioweapon Defense Mode, the positive pressure inside the cabin minimizes the amount of outside air that can enter the vehicle.

Note
Some gases, such as carbon monoxide, are not effectively removed by activated carbon.”

https://www.tesla.com/ownersmanual/cybertruck/en_us/GUID-CFA216A5-F2CC-416F-97E8-8560E0CC4161.html

Right. It says when it’s “on” but is it better to have it in biodefense mode or completely off when driving through fire zones?

 

[CyberGus]

Right. It says when it’s “on” but is it better to have it in biodefense mode or completely off when driving through fire zones?

Probably “recirculate” is the right answer

 

[HaulingAss]

Right. It says when it’s “on” but is it better to have it in biodefense mode or completely off when driving through fire zones?

If it's just smoke, I would probably just run a low to medium-low fan speed because I don't think a lot of air leaks around the door and window seals anyway, and I would want the lower volume of air through the filter for better filtration of tiny particles and absorption of gases. Putting recirculate on would likely further improve filtration (and thus inside air quality) as long as it's designed in such a way so as to not depressurize the cabin (which could potentially increase air infiltration from outside). I assume the system is engineered to keep (at least) a slight positive pressure in the cabin no matter which mode you are in.

If it was a biological attack with a highly infectious virus, I would probably use Bio-defense mode to pressure the cabin to eliminate the chance of leakage. The faster the vehicle is travelling through the air, the more useful Bio-defense mode is (because it has enough power to overcome forced infiltration at higher vehicle speeds). I think Bio-defense Mode could be improved by using a lower fan speed and putting motor actuators on the exit portlets to close them. This would pressurize the cabin without requiring very high fan speeds. But that would require additional hardware for minimal benefit statistically. Probably not worth it.

I would never turn off the climate control unless the vehicle or the climate system had a fault that would benefit from that. In general, it should always be on and filtering. I suppose there could be a plume of toxic concentrate so deadly, even after running through the filter, that it would be safer to have it off. But I can't think of what that would be. I would probably take my chances with a low fan speed and recirculate (to minimize the amount of outside air drawn in).

 

[tmeyer3]

Biodefense mode works because of the pressure created by the maxed fan speed. It creates a positive pressure in the cab, forcing other seams around the vehicle to become sealed ingress. Clean rooms work the same way.

Positive pressure rooms (the truck) are protecting environments. Negative pressure rooms are isolation environments. Keep the fan maxed.

For those interested:
https://airinnovations.com/blog/negative-positive-pressure-rooms-hospital-infection-control/

 

[NSCyber]

Biodefense mode works because of the pressure created by the maxed fan speed. It creates a positive pressure in the cab, forcing other seams around the vehicle to become sealed ingress. Clean rooms work the same way.

Positive pressure rooms (the truck) are protecting environments. Negative pressure rooms are isolation environments. Keep the fan maxed.

For those interested:
https://airinnovations.com/blog/negative-positive-pressure-rooms-hospital-infection-control/

Silly questions:

Does it also bring in outside air into the vehicle through the filter? There is no way right now of creating that positive pressure in the car with the fan on only and not bringing in any outside air? Would this be recirculate mode?

 

[tmeyer3]

Silly questions:

Does it also bring in outside air into the vehicle through the filter? There is no way right now of creating that positive pressure in the car with the fan on only and not bringing in any outside air? Would this be recirculate mode?

Interesting questions! Yes, it does bring outside air in, which is why HEPA filters are so important. Keep in mind that pulling air into the vehicle is necessary to create a positive pressure environment. Recirculating air cannot create a positive pressure room in same way that you can't pull yourself off the ground by pulling your bootstraps--you need to be constantly adding new clean air in order to create a positive pressure.

In a dangerous air situation like dense smoke or a biowepon attack, you're much better off relying on the HEPA filter + positive pressure than recirculating air without pressure to prevent unfiltered ingress from outside.

Hope that helps! In short, physics doesn't allow positive pressure in recirculation mode.

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