Tesla HEPA Filter Bioweapon Defense Mode Review

Fires, air pollution, and now pandemics are unfortunately becoming more and more common these days as global warming increases and our worldwide population grows. When the tragic fires struck California back in November 2018 and again in 2020, the air quality levels in the San Francisco Bay Area and Los Angeles region had extreme levels of pollution, enough that avoiding almost any outdoor activity was recommended. For those who were lucky enough to have Tesla Model X or Model S electric vehicles with the HEPA filter installed, they were able to take advantage of a special mode called “Bioweapon Defense Mode” that Tesla Motors claims is 100X more effective than regular car filters.  It not only removes smoke particles, gaseous pollutants, and fine particulate matter, including mold spores but also helps against allergens for those with asthma or other allergies.

According to Tesla’s marketing statement:
“Inspired by the air filtration systems used in hospitals, clean rooms, and the space industry, we developed a HEPA filtration system capable of stripping the outside air of pollen, bacteria, and pollution before they enter the cabin and systematically scrubbing the air inside the cabin to eliminate any trace of these particles. The end result is a filtration system hundreds of times more efficient than standard automotive filters, capable of providing the driver and her passengers with the best possible cabin air quality no matter what is happening in the environment around them.”

Does the Tesla HEPA Filter keep out COVID?

While HEPA filters are designed to filter out 99.97% of particles with a diameter of 0.3 micrometers (microns) [reference], a virus-like COVID-19 is smaller, approximately 0.125 microns. While different HEPA filters may do a better job filtering out particles than others, there’s no guarantee that the HEPA filter will live up to the 99.97% claim for this virus. That said, Tesla Bioweapon mode also produces positive pressure in the cabin, so outside air doesn’t enter, further reducing the chances of contamination. Have a Tesla Model S or X with Bioweapon mode? You can turn it on when you’re driving in traffic near a crowded area to help avoid contamination. Remember, it’s not a substitute for staying at home, keeping your distance or wearing a DIY mask when outside to avoid coronavirus.

Does the Tesla Model Y Have a HEPA Filter?

Yes, as of late 2021, the Model Y has the HEPA filter standard. In fact, they produced this video to show its effectiveness versus a typical vehicle filter:

Does the Tesla Model 3 Have a HEPA Filter?

No, the filter is so big, it would not fit in the Model 3. Here’s a photo of CEO Elon Musk holding a giant Model X HEPA filter vs a normal car filter:

According to a recent tweet by Elon Musk in regards to the Model 3’s air filter:

While it won’t protect against a military-grade bio attack, the built-in air filter in the Model 3 works very well. A tip from Elon for best possible air filtration and clean air: “Set airflow to recirculating mode & manually raise blower speed to 5 in Model 3 for best air quality. Air filters are smaller than S/X, so clear air is achieved by circulating through filter several times.”

Here is a video showing a Tesla Model 3 owner testing the recirculation mode.  After about 10 minutes of being on recirculation, the air is as clean as using a HEPA filter.  Quite impressive!

Tesla HEPA Filter Tests & Measurement Values

Tesla tested the HEPA filter Bioweapon Defense Mode by putting a Model X into a large bubble and testing PM 2.5 (fine particulate matter – the most dangerous type of air pollution) inside the vehicle. Note that Air Quality Index (AQI) is a different, but related measurement to PM2.5 levels. For more information on AQI and PM2.5 levels, see this Wikipedia article. Here’s how the testing setup looked:

Normally the PM 2.5 level for good quality air, according to the EPA, is below 12 µg/m3. Above 150 µg/m3 is considered unhealthy.  For reference, the air in Beijing averages around 56 µg/m3 and 20 µg/min Los Angeles. For this test, Tesla pumped particles at 1000 µg/m3 (very dangerous levels) to see how effective the HEPA filtration system in the Model X could be.  Within two minutes in Bioweapon mode, it was able to bring PM 2.5 levels to almost undetectable levels.

How to Use Bioweapon Defense Mode

If you have a vehicle with the HEPA filter and Biodefense mode, to turn it on, you press the climate controls and then press the biohazard symbol:

You’ll then hear air flow go to maximum as it creates a positive pressure inside the cabin to prevent outside air from leaking in.  In addition, any outside air will now go through the HEPA filter via the HVAC (Heating, Ventilation, and Air Conditioning) system.

Does the HEPA Filter Work in Automatic Climate Mode?

From what we can tell, the HEPA filter does not seem to be used when climate controls are used normally in automatic mode. HEPA air filtration is only employed when you turn on the Bioweapon Defense setting.

Our Test

We tested a Model X with a HEPA filter installed during November 2018 when California wildfires blanketed the Bay Area with unhealthy levels of smoke particles (PM 2.5 of over 200 µg/m3).  Here’s what we found.

Test Equipment: DM502 Dienmern / Langder HCHO TVOC PM2.5 PM10 Monitor
Other sensors: EG AirM5 Sensor (China),

  • We first measured the air quality outside at around 216 µg/m3.
  • After going into Bioweapon mode, the air quality was measured at around 6 µg/m3 after a couple minutes.
  • We turned off Bioweapon and switched to automatic. Reading was 25 µg/mafter about 10 minutes.
  • After we opened the Falcon Doors, the air quality jump back up to the original high level very quickly.

So there you have it.  The HEPA filter works as advertised.  If you’re in a smoky situation, just be sure to activate the Bioweapon mode to get the full benefit of the giant HEPA filter.


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