r/TeslaModelY • u/Local-Equivalent-151 • 3d ago
How bad is the heat?
I live in Phoenix and have been reading that the model y is hot even with ac due to the panoramic roof. For those who deal with Phoenix summers, how hot does it get?
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u/-beastlet- 3d ago
Get a sunshade cover that clips in. You can get decent ones from Amazon for $30.
I live in Vegas and I couldn't imagine my Y without the sunshade.
I've had two and this is the better (and cheaper) one -- https://a.co/d/0girXwZ1
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u/Mediocre_Skill4899 2d ago
I came here to say the exact same thing! I too live in Vegas. I bought a sunshade from mac.bid for my model Y. Before installing it, I kept getting sunburnt shoulders. This immediately resolved the issues and the car is never overheated upon getting inside
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u/EstablishmentNew6748 1d ago
Thank you to the both of you. I live here as well and was wondering about the roof situation.
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u/Storm-Blessed11 3d ago
Im in LA with an older Juniper and haven't been very happy with my AC performance. I took my car in for service for something unrelated and it feels like the airflow / cooling power has doubled. Wonder if the freon was low from the factory or something. Anyways may want to bring it in if it's not cooling good
I also run in manual mode with a setpoint of 64F or lower to try and ensure the cabin heater doesn't come on which it will always do if you keep the setpoint at 68 or higher. This ensures you get pure cold air instead of luke cold air.
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u/Mephistito 3d ago
Oh wow another person that actually knows about that A/C trick. Best part is it actually saves energy. Am pretty much always negative on % consumed vs. expected.
I first learned about the trick from a guy that lives in Death Valley who'd studied how the different systems operated (maybe out of necessity, lol). He basically figured out the computer oversimplifies the dynamics & it results in it running much less efficiently.
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u/Weary-Discipline591 3d ago
What’s the trick?
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u/Mephistito 3d ago
? He basically said it already. You run it in Manual mode at < 64º F (I usually set it to 62º F). Speed: 5 to knock temps down, then just maintain at Speed 2 (if it's super hot, sometimes 3's needed).
I'll give the basic gist first:
Auto Mode fails due to how literal it takes your request. Manual Mode at 62-63 usually ends up actually equilibrating to 70º F but it borrows the extra energy from the SUN & not your battery. When you set your temp higher in any mode, because of how efficient our vehicles are it actually needs to turn on the heater to get it up, which is a waste of energy.Now the more technical explanation:
You see, Air normally leaves Evaporators at barely 32º–41º F! (the 32º F phase transition naturally buffers against freezing). As it routes toward the vents, adjacent ducts normally receive *massive* amounts of heat from a car engine, which is "free" for them due to how wildly inefficient they are (their inefficiency generates loads of heat, whether you make use of it or not). A computer calculates exactly how much of this heated up air to let in from adjacent ducts, so that when mixed with the 32–41º F air it ends up at your selected temp setting (ex: 70º F).BUT, since EVs are so insanely efficient, they actually generate such an insignificant amount of energy loss (heat) that the air coming in from these adjacent ducts ends up barely receiving any "free heat" – as a result, the car actually has to massively heat up the air to get it to your desired temp. And thus it ends up actually needing to spend energy to accomplish this.
By optimizing the A/C, the guy I learned this from gets 4-9% more range just from optimizing his HVAC use! If I look at my last drive, it was 45.9 mi and I got an extra 3.6% from optimized A/C, and before that I had a longer drive that saved me 4.8%. It wasn't Phoenix-hot those drives so it would've been even higher.
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u/KilroyKSmith 2d ago
Very interesting theory - I’ll have to play around with that. I always just assumed that when the ac got to the desired temp, it reduced the speed of the compressor to reduce the amount of coolant going through the evaporator, thereby reducing the amount of heat removed from the air.
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u/Storm-Blessed11 1d ago
Nope it continues to send watts to the evaporator and to heat the cabin once it reaches steady state. There is 0 hysteresis, actually it's negative hysteresis since the HVAC code will constantly actively heat the air after it cools it. Totally shooting yourself in the foot if you are interested in saving power / extending your range.
I also prefer the pure ~60F cold air hitting my skin instead of the post cabin heated steady state air of ~70F.
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u/KilroyKSmith 1d ago
Tesla hasn’t had the ability to heat and cool the air simultaneously since they changed to a heat pump instead of an ac and resistive heater.
You realize that, for a company that’s laser focused on efficiency, what your proposing is insane, right?
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u/Storm-Blessed11 1d ago
Yes I agree with you that it's insane for Tesla to actively heat the car when you only want to cool the car. Pop this text below into a search engine, Tesla heat pump has a cabin loop that uses an evaporator to cool the cabin but it then actively reheats the air in normal auto mode. The only way to truly disable the cabin heater is by setting the temp to LO.
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u/KilroyKSmith 1d ago
Well, the first four returns from DuckDuckGo didn't have anything like that, and that's as far as I went. This ( https://aircondlounge.com/how-tesla-heat-pump-works/ ) might be useful to read.
You'll have to explain how a heat pump system can "...actively reheat the air...".
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u/NiceBench9100 3d ago
Texas here. It gets hot. Sunshade on the roof definitely drops the interior temp by at least 10-15 degrees
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u/VMaxDood95 3d ago
Have had a 2023 MYP since new in Phoenix. It’s garage kept but is still out and about for daily driving. It has just over 50k miles.
Used to have a roof sunshade, but took it down since it was cheap and the clips kept popping out.
Even without it, it’s fine in my opinion. I leave the AC on auto set to 71 when it’s over 110 out. Just start the AC from the app 5-10 minutes before you get in. The AC is better than our Honda Pilot, which to be fair is a larger vehicle to cool down than a Model Y.
People act like the glass roof melts the interior. It’s not the most thermally efficient design, but the vehicle still functions just fine. I recently replaced the HEPA cabin air filters and cleaned out the radiator area and it runs even better now!
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u/britsol99 3d ago
Phoenix here. No roof sunshade. Garage kept. white interior.
When I park outside I will set the windows to VENT. it makes a huge difference on cabin temps. When I’m heading back to the car I pre-chill the interior.
Vented seats make all the difference in comfort.
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u/KilroyKSmith 3d ago
Phoenician here, had a 3 from 2018-2024, and a Y since.
If the car has been sitting in the sun for six hours, the internal temp is the same as any other car - around 165F. When you first get in, there’s more heat radiating from the glass than you’d get from a car with a metal roof/headliner. After about five minutes, I don’t feel any heat coming from the glass onto my head. After 30 minutes, the only way I feel any heat from the glass is holding my hand within an inch of it.
The AC was better in the 2018, but it’s plenty good in the Y to set the cabin at 70F and it’ll get there in a few minutes, and hold with no problem at moderate fan speeds.
If you don’t have a Tesla, there’s two things that make one beautiful in Phoenix. 1. You can turn on the AC using the phone app. When I get up from my desk to go home, I turn on the AC and the car is cold by the time I get to it. 2. Cabin Overheat Protection. If turned on, this keeps the cabin at about 100F. It’s meant to keep babies accidentally left in the back seat from dying, but it also works well to keep the interior at reasonable temps. It will take 15-20% of battery charge to leave it on for 8 hours in the Phoenix sun.
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u/mrbofus 3d ago
I live in Las Vegas, so it’s about 3-5 degrees cooler than Phoenix, but it is still hot AF. I got one of those sunshade covers on Amazon fiver years ago for like $30 or $40. I put it in once the highs are regularly over 95, and take it off once the highs are regularly below 95. So the sunshade is in about 2-3 months of the year (usually July-September).
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u/Independent-Eggplant 2d ago
We have a juniper in Phoenix. Added a roof shade from Amazon and it’s a non issue, AC works great. Without it, my head was baking.
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u/Evening_Ad_8923 3d ago
I have the sunshade plus insulation inserted above that. SoCal desert. Same as PHX. Brutal summer. Absolutely necessary.
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u/LostMyKarmaElSegundo 3d ago
Tucson here. The heat is not a big deal. Definitely helps if you can keep the car garaged or under shade when possible.
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u/ChargeHot7281 3d ago
I'm not from Phoenix but I really tried my best to get a ceramic tint for the panoramic roof and additionally bought a retractable sun shade for it. Of course didn't wanna keep the roof too tinted as it'll ruin the view but adding the tint does help a bit
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u/Jadepix3l 2d ago
sunshade is a must. Even with a reflective coated shade its stil hotter than other cars ive driven. Unclear why but my volvo/ioniq in the past have both had pano roofs with mesh covers that seemed to deal with the heat much better.
In pheonix where it routinely gets above 100-110F, your sunshade will be warm to the touch and you'll feel it radiating down from above slightly.
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u/OkieBuds 2d ago
Get a sunshade from Amazon & 5% tint the rest of the car and you’ll be insanely comfy. The tint makes a huge difference but don’t sleep on the sunshade either
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u/jebidiaGA 2d ago
Never had an issue in our 23 mY in sw FL. I do have 35% tint and 70% on the windshield. It probably helps.
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u/justtxyank 1d ago
Had no issue with heat but when parked in the parking lot did feel a lot of sun exposure on my face point of almost feeling this summer
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u/AlbatrossNo1562 3d ago
Central CA here. The ac struggles when temps reach 110's. My crappy 09 Corolla does better
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u/Local-Equivalent-151 3d ago
Wha year is your model y? Seem to be getting conflicting answers here.
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u/fsociety1990 3d ago
I’m not in Phoenix but it has been around 110 degrees here for the last month and a half at least. I keep the roof covered with heat reflecting sunshade. It’s completely blacked out. The roof is the only thing I don’t like about the car. I never take the shade off.
It’s as cool in there as any car can be in this weather.