Why does my Tesla stink?

Posted on Oct 21, 2024

First off I should say that I absolutely love my Tesla Model 3. It very well might be one of my favorite cars of all time and it’s by far the best daily driver I could ask for.

It does have a few problems

Range
Elon Musk
Charging availability
Elon Musk
No Amazon Prime Video

But by far the strangest problem is the air conditioning. It stinks. Like literally, Teslas are known to develop a smell after months of use and it’s not just because the drivers don’t shower.

Every air conditioning system is just a heat pump. I’m not going to go into detail on the thermal dynamics of heat pumps, go ask a HVAC guy or something, but basically refrigerant runs through the system. The refrigerant is under pressure and is a liquid. When the refrigerant is able to expand and eventually change phases from liquid to gas, due to some really cool physics it cools down. Then you can blow air around the the refrigerant lines to make the air cold. As you might imagine, warm air blowing over cold lines causes condensation to form on the bits inside and surrounding the evaporator. This condensation is normally pumped out of the car.

What makes Teslas special

They use the same system to cool the battery as they do to cool the cabin. So compared to most cars, they have a much more powerful air conditioning system. Which means that, compared to other cars, Teslas make a lot more condensation. If you ever spot a Tesla supercharging station take a second to look at the ground, you might notice some small puddles forming under the cars. That’s condensation from the cooling system.

So why does this matter

This excess of condensation causes the air coming from the air conditioner to be really humid. Which just sucks. This causes moisture to build up in the air conditioning vents and filters which can lead to bacteria and mildew forming in them. Which causes the whole car to stink. It also just makes the car so humid every time you drive it with the AC on.

The solution

Tesla is aware of this problem. They have previously pushed software updates to try to address it. Basically, Teslas will just stay on for up to 30 minutes after you leave the car. During this time they will run the fans in the car at near full blast without the AC on. The goal is to evaporate any water that’s formed in the AC vents. EXCEPT ALL THAT WATER JUST MAKES THE AIR EVEN MORE HUMID AND ALL THAT HUMID AIR JUST BLOWS INTO THE CAR’S CABIN. So that means that I’ll be leaving my Tesla, the air is perfect, I step outside, sunny day, no humidity, the air is perfect, and then I’ll get back in my Tesla later and it’ll just be kinda humid in there. Oh yeah, and it still stinks a little.

Now in reality it’s not that bad. The smell is honestly really faint and something like a Little Tree air freshener will completely overpower it. My friend described it as “smelling like a pool”. You also just go nose blind to it after a while. The humidity is also pretty faint. I live in a desert so I’m pretty used to dry air, air with a little moisture in it feels just weird. The best thing I can compare it to is standing right outside Roscoe’s Chicken and Waffles in Long Beach, California at exactly 1 pm in the summer. Also turning off recirculation stops most of this from happening but also severely impacts the efficacy of the air conditioner. Also Also you can crack the windows remotely from the app which also helps. But it’s such a random problem for a car to have and I’ve never heard of any other car having this issue so it just completely captivated my brain. Hence the blog post.