Heat pump vs Resistive on Model 3

[GZDongles]

This other TeslaBjorn video shows that the heat pump equipped Model 3 heats up within 1 minute, and is way more efficient than the 2020 Model 3 with the PTC heater.

I don't think anyone has convincingly compared total heat output yet, but anecdotally the total heat output from the heat pump is at least as good as PTC down to -25C. Tesla Bjorn has some great videos staying overnight in the car and driving at -25C, and the heat pump has always been more efficient than PTC at all temperature ranges. For road trips, one of the big benefits is the ability of the heat pump to scavenge waste heat from the battery after supercharging.


Also, as a side note, I have experienced temperatures down to -8F this winter, and my car has never proactively heated the battery without me preconditioning. Checking Scan My Tesla, it looks like the temperature target for active battery heating (of course excluding heating before charging) is -27F. So there are very few situations where anyone should be worried about the car wasting energy heating up the battery for the winter!

 

[Chris Cronin]

If you are trying to justify a new car, ask yourself if you need the range...
They both get hot and heat fast enough.
The heat pump is not like your home model, much more advanced with the ability to move heat to/from multiple areas. It's invaluable in colder areas (mine) where we can purchase the SR+ and average 250wh/mi for our first 1K miles (20's or less at night and 30's daytime since we purchased in mid Jan. - just general nasty New England winters)

Hi! I'm from Maine and looking at a used M3 or MY. What mileage loss is expected in the M3/MY with the resistive heater vs heat pump? Ive seen mixed reviews about the heat pump in cold climates (such as Maine) and am wondering if the resistive heater is better? The 2021 MY I am looking at has the EPA range of 326mi, so 261mi with 80% charge. The 2020 M3 I am looking at has the EPA range of 322mi, so 257mi with 80% charge. I am having a really hard time with deciding between the resistive heater and heat pump option. My commute for the next few years is sadly 62 miles one way.

 

[Two-rocks]

Take the epa ratings with a large grain of salt. Use the wh/mile that people publish , combined with battery capacity of the model you are looking at - less degradation and charge level - to get your practical range.

The heat pump/ octovalve is superior at heat management - used for more than cabin air.

 

[Chris Cronin]

Take the epa ratings with a large grain of salt. Use the wh/mile that people publish , combined with battery capacity of the model you are looking at - less degradation and charge level - to get your practical range.

The heat pump/ octovalve is superior at heat management - used for more than cabin air.

Do you know how much the cold eats away at your available mileage for the resistance heater vs heat pump?
What temperature for the RH/HP do you start seeing those drops?
If getting used, what year would be the oldest you’d go for the M3/MY?
I love the space of the MY however I don’t see it holding its value as much due to the $7,500 rebates coming next year - due to price I don’t believe the M3 will get any rebates.

 

[GtiMart]

as soon as you need heat for the cabin, you'll spend energy for heating, it's as simple as that. The farther the exterior temp is from interior target, the more energy you'll spend. Moving at highway speeds will cool the cabin more than being stationary.
If outside temp is higher than target you're using AC or heatpump to cool though, which also consumes energy. For a heatpump the question would be "how much farther from your summer temperatures are you in winter". For resistive it's harder to tell but since heatpumps are more efficient, it will take less cold...

Cold temperatures mean denser air you are pushing through, and that is worse at highway speeds. This is an additional expense, separate from heating.

If like me you run winter tires, they probably have a higher rolling resistance than your summer tires, which is another source of consumption.

Finally, if you drive in slow or water on the ground, that also augments consumption.

 

[Chris Cronin]

as soon as you need heat for the cabin, you'll spend energy for heating, it's as simple as that. The farther the exterior temp is from interior target, the more energy you'll spend. Moving at highway speeds will cool the cabin more than being stationary.
If outside temp is higher than target you're using AC or heatpump to cool though, which also consumes energy. For a heatpump the question would be "how much farther from your summer temperatures are you in winter". For resistive it's harder to tell but since heatpumps are more efficient, it will take less cold...

Cold temperatures mean denser air you are pushing through, and that is worse at highway speeds. This is an additional expense, separate from heating.

If like me you run winter tires, they probably have a higher rolling resistance than your summer tires, which is another source of consumption.

Finally, if you drive in slow or water on the ground, that also augments consumption.

What year and model do you have? Being in Maine do you believe the resistive heater might be better? Ive seen some posts that the heat pump isnt always keeping up when its cold however, people aren't defining what "really cold" is. My guess is sub-zero F.

 

[Ther0ck]

What year and model do you have? Being in Maine do you believe the resistive heater might be better? Ive seen some posts that the heat pump isnt always keeping up when its cold however, people aren't defining what "really cold" is. My guess is sub-zero F.

We had a couple of -15c to -20c in Montreal last winter when we got our car. No issues.

 

[Chris Cronin]

We had a couple of -15c to -20c in Montreal last winter when we got our car. No issues.

What year and model do you have? What reduction in range did you see

 

[GtiMart]

I have a 2020 resistive. Plenty of people have heat pumps here in Quebec where we can get down to -30C temperatures. Apart from the actual heatpump problems which were fixed under warranty, I believe the heat pumps can handle the cold just fine. I haven't heard major complaints on the local facebook groups.

 

[Chris Cronin]

I have a 2020 resistive. Plenty of people have heat pumps here in Quebec where we can get down to -30C temperatures. Apart from the actual heatpump problems which were fixed under warranty, I believe the heat pumps can handle the cold just fine. I haven't heard major complaints on the local facebook groups.

How much range are you loosing when it’s say -30C, 0C, etc.
do you feel like you can’t run the heat because you’re loosing too much range?

 

[GtiMart]

I've never "not used the heat". I don't understand people that say use the seat heaters instead. I need to survive in the car, not freeze to death, I will certainly use the heat. Winter means somewhat more supercharging stops on long trips, that's all. Nothing more. What I could do directly in summer might require a stop somewhere along the road for a few minutes, no big deal. Once you get over range anxiety, once you experience superchargers and see that it'S really pretty fast, you'll forget about this "detail".

 

[GtiMart]

I guess I should add one note: this type of thing WILL matter, but only if you are on the fringe of the supercharger support. It is the case in some more remote areas around here, which is why some people have opted for heat pumps. Some trips that might have been a stretch in resistive in winter might become less stressful with a heat pump. Those a fringe cases, not broadly applicable. In the US there are so many superchargers that this comment doesn't apply.

 

[Chris Cronin]

I've never "not used the heat". I don't understand people that say use the seat heaters instead. I need to survive in the car, not freeze to death, I will certainly use the heat. Winter means somewhat more supercharging stops on long trips, that's all. Nothing more. What I could do directly in summer might require a stop somewhere along the road for a few minutes, no big deal. Once you get over range anxiety, once you experience superchargers and see that it'S really pretty fast, you'll forget about this "detail".

It’s nice hearing you don’t turn off the heat and use just seat warmers. How much range are you loosing on the colder days

 

[GtiMart]

I thought I had posted my TeslaFi graph here but I guess it's in another thread. I don't have a lot of "long" trips in winter so the data isn't excellent, but I can see down to 52% efficiency (as compared to the EPA rating) in the coldest, say -20C to -25C days. However, compare that with my efficiency in warm and hot days which hovers around 80% of EPA. Basically, I never do EPA . Said another way, I lose 20% in summer and lose up to around 50% in the worst trips I've done in winter. Note that those winter trips were quite short. I would expect losing a bit less than that, especially if the trips were longer since the biggest draw is initial heating up of the cabin and battery.
Note that I drive 121kph on the highway (allegedly), which doesn't help, and I have ultra performance all season tires which are stickier than stock (with no aero caps) EDIT: And real winter tires in winter, which don't help either.

 

[Chris Cronin]

I thought I had posted my TeslaFi graph here but I guess it's in another thread. I don't have a lot of "long" trips in winter so the data isn't excellent, but I can see down to 52% efficiency (as compared to the EPA rating) in the coldest, say -20C to -25C days. However, compare that with my efficiency in warm and hot days which hovers around 80% of EPA. Basically, I never do EPA . Said another way, I lose 20% in summer and lose up to around 50% in the worst trips I've done in winter. Note that those winter trips were quite short. I would expect losing a bit less than that, especially if the trips were longer since the biggest draw is initial heating up of the cabin and battery.
Note that I drive 121kph on the highway (allegedly), which doesn't help, and I have ultra performance all season tires which are stickier than stock (with no aero caps) EDIT: And real winter tires in winter, which don't help either.

Do you plug in your Tesla at home? If using a 60amp breaker with “warm up”, would that help?
Also, is warm up only doing the cabin/windows or is it also warming the battery pack?

 

[GtiMart]

I typically park in a heated garage and I do have a wall connector. Most people around here don't have garages. Yes, the act of charging will heat the battery. You can also precondition in the morning, ideally while plugged, so that you top up whatever energy gets used to preheat and leave home with a "full" and warm battery. You don'T need to, the car will work just fine with a frozen battery. It'll be less efficient, and you won'T have regen for a while, but the car is perfectly driveable. Unless you need your full range for a trip, the actual range loss won't matter.

 

[Ther0ck]

What year and model do you have? What reduction in range did you see

2022 RWD. Depends on the conditions, driving habits, pre heating or not, etc.

But anything below -5c, I use 438km/2=219km. If I get higher useable km, I give myself a tap on the shoulder.

But the rule of thumb, is 30% loss.

 

[pt19713]

Do you know how much the cold eats away at your available mileage for the resistance heater vs heat pump?
What temperature for the RH/HP do you start seeing those drops?
If getting used, what year would be the oldest you’d go for the M3/MY?
I love the space of the MY however I don’t see it holding its value as much due to the $7,500 rebates coming next year - due to price I don’t believe the M3 will get any rebates.

I don't have a 2018-2020 Model 3 to compare since my wife and I have heat pumps in both vehicles (2020 Y LR, 2021 3 P). I have 3 full summers and 2 winters in my Y, 2 summers and 1 winter in the 3. Ironically, the car is less efficient in the summer. I'm pulling my info from the car with the Scan My Tesla app.

From what I've seen over the years, expect the Model 3s with the PTC heaters to pull 1500-2000 watts in the winter. The vehicles with the heat pump will pull around 600 watts, plus 100 watts for each seat warmer active, so for every hour, expect the older PTC vehicles to require about 1000 more watts.

My drive to my in-laws is about 65 miles. In the winter, my efficiency is around 260 Wh/mi, or 3.84 miles/kWh. In the summer, the same drive is around 280 Wh/mi, or 3.57 miles/kWh. I have ceramic tinted front windows, no tint on the windshield, no additional tint over the factory privacy glass and roof/hatch. The car works harder to cool the cabin on sunny summer days, pulling over 1200 watts when it's 86+ and sunny.