Heat pump

[LeoH]

Do you mean before? Having previously lived in Chicago for over a decade, reliable heating is definitely a necessity.

I meant AFTER. I do not want a heat pump anywhere near my vehicles UNLESS there is an aux heat source with it.

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[LeoH]

Don't really understand the sentiment against heat pumps. Our Model Y heat pump has been unbelievably good this winter, blowing excellent heat, pretty much immediately down in the single digits. Our typical highway economy is around 380-400 wh/m, at around 70 mph, which I think it's pretty crazy impressive. Maybe their specific design will require service down the line, but the tech works literal wonders. People who have never owned EVs (and who won't get to use the supercharger network) need to get in a new headspace where efficiency is no longer an afterthought. It can be the difference between getting there and not. We had a bitter cold day last week where a 30 mph headwind dropped our highway efficiency to nearly 600 wh/m, changing our travel plans significantly. Maximizing efficiency where you can is important.

As someone who owned 2 EVs, from a huge family of EV owners, model 3 heat pumps took a massive shit this winter in Chicago. Also, our commercial building heat pumps took a dump as well. So would I rather drive 200 miles very uncomfortable or drive 120 miles very comfortable? Give me 130 miles.

See, single digit temperatures on their own might not be that bad, but adding -25 Windchill and you got yourself a deep freezer on wheels. -25 windchill does not mean its -25, but it means materials would lose heat as the same rate if it was -25; that's not heat pump weather.

 

[astonius]

As someone who owned 2 EVs, from a huge family of EV owners, model 3 heat pumps took a massive shit this winter in Chicago. Also, our commercial building heat pumps took a dump as well. So would I rather drive 200 miles very uncomfortable or drive 120 miles very comfortable? Give me 130 miles.

See, single digit temperatures on their own might not be that bad, but adding -25 Windchill and you got yourself a deep freezer on wheels. -25 windchill does not mean its -25, but it means materials would lose heat as the same rate if it was -25; that's not heat pump weather.

Didn’t they find an issue with the Tesla heat pumps and issue a software update for them to fix this issue?

I get the impression this might be “one size fits all” opinion of heat pumps, either from prior experience or from Tesla’s mishap which was eventually corrected. If heat pumps were this terrible I don’t think so many manufacturers would be going to the trouble to add them to their vehicles.

 

[Craigins]

Didn’t they find an issue with the Tesla heat pumps and issue a software update for them to fix this issue?

I get the impression this might be “one size fits all” opinion of heat pumps, either from prior experience or from Tesla’s mishap which was eventually corrected. If heat pumps were this terrible I don’t think so many manufacturers would be going to the trouble to add them to their vehicles.

Everything I've read says they stop functioning well at around 0F.

Most EVs seem to be designed for the coasts, so this isn't an issue for the majority. However as they spread to the upper Midwest, it will be a problem.

I will be glad for the non heat pump R1T. Chicago and Northern Wisconsin can get pretty cold in the winter.

 

[timf]

I didn't realize what an issue the heat pump was, but I had a conversation with a Model Y owner while waiting to pick up my Model X from the service center this weekend and he said it basically doesn't work below 20 degrees. I would gladly do without such a system in my R1S unless there was also a supplemental heater for cold days.

 

[Engi_Nerd]

As someone who owned 2 EVs, from a huge family of EV owners, model 3 heat pumps took a massive shit this winter in Chicago. Also, our commercial building heat pumps took a dump as well. So would I rather drive 200 miles very uncomfortable or drive 120 miles very comfortable? Give me 130 miles.

See, single digit temperatures on their own might not be that bad, but adding -25 Windchill and you got yourself a deep freezer on wheels. -25 windchill does not mean its -25, but it means materials would lose heat as the same rate if it was -25; that's not heat pump weather.

I'm in Rochester, not exactly known for balmy weather, and at no point have I even had to think about my heat. Blanket statements like "All Model 3s in Chicago had their heat fail" or "heat pumps don't work in the cold" are simply false. Tesla has too much to lose to willfully deploy HVAC systems that aren't designed to cope with the well-established temps in the northern hemisphere. Also, Teslas are becoming as common as Camrys among STEM workers. Having family with EVs is nothing special. I personally know prob 20+ people with Teslas and none have had heat issues locally (service issues on the other hand...).

The problem Tesla has faced with their heat pumps have not been from the inability to cope with cold temps, but from QC issues. Failing sensors, inlet slats getting jammed with ice, etc. They'll get it sorted eventually, as they do with most things.

 

[Lil'Dave]

Two winters with our MY heat pump with no issues. We've been well below zero and had ample heat.

The 2013 Leaf was a different story. When the resistance heater failed in mine, the heat pump couldn't hold temp when it dropped below 40 if I remember correctly. The lease was up and the dealer had no interest in fixing it for me (failed with 2 weeks left of lease).

Regarding Rivian, I was told the heat pump has been under development and wasn't ready in time for the R1 release. This was back late last year.

 

[zefram47]

My MINI has a heat pump and I had no issues in our below zero weather a couple weeks ago.

 

[no4bit]

@EVnewb and @LeoH thanks for the explanations! I don't fully understand how heat pumps work and thought having one would be a good thing to extend range in colder climates.

 

[godfodder0901]

Two winters with our MY heat pump with no issues. We've been well below zero and had ample heat.

The 2013 Leaf was a different story. When the resistance heater failed in mine, the heat pump couldn't hold temp when it dropped below 40 if I remember correctly. The lease was up and the dealer had no interest in fixing it for me (failed with 2 weeks left of lease).

Regarding Rivian, I was told the heat pump has been under development and wasn't ready in time for the R1 release. This was back late last year.

My MINI has a heat pump and I had no issues in our below zero weather a couple weeks ago.

Residential heat pumps typically have a resistive heating element in order to supplement the heat pump in lower temperatures. I'm wondering if your vehicles have the same feature, and the resistive heating kicks in, making it seem as if the heat pump is sufficiently supplying hot air?

 

[Gsxr150]

Don't really understand the sentiment against heat pumps. Our Model Y heat pump has been unbelievably good this winter, blowing excellent heat, pretty much immediately down in the single digits. Our typical highway economy is around 380-400 wh/m, at around 70 mph, which I think it's pretty crazy impressive. Maybe their specific design will require service down the line, but the tech works literal wonders. People who have never owned EVs (and who won't get to use the supercharger network) need to get in a new headspace where efficiency is no longer an afterthought. It can be the difference between getting there and not. We had a bitter cold day last week where a 30 mph headwind dropped our highway efficiency to nearly 600 wh/m, changing our travel plans significantly. Maximizing efficiency where you can is important.

Yeah I don't get it either. Our Y has been great as well.

 

[JoulesVerne]

At 0° F there is still heat in the air the can be concentrated via heat pump and sent into the cabin. At 0° Kelvin there is not. 0° F is 255° Kelvin - quite warm!

 

[sub]

On Tesla's design, it is more like a geothermal heatpump than a traditional outside-air driven heat pump.

The "outside" end of the heatpump is the motor coolant which is always going to be warmer than the air when you are driving. And if the motors are too cold to pull heat from, the motors can be told to produce more heat. Even at a standstill, the motors can generate a bunch of heat.

It doesn't actually work like this, but imagine both the forward and reverse circuits enabled at the same time. Lots of heat, but no motion.

The motors running in heat-producing mode can produce more than enough heat to keep the system working in even the coldest conceivable situations. If the motors are producing enough waste heat to warm the cabin, you get "free" cabin heat. If not, you still get heat but it have to pay for it. It will always be at least slightly more efficient than a resistive heater any time the vehicle is moving.

There is no downside other than increased complexity which opens to door to more failures. And as others have mentioned, there have been a lot of failures with Tesla's system.

 

[Polecat]

I’ve got a heat pump on my Polestar 2 and being in Minnesota with it has been fine this winter. Plenty of days taking it out in -5f and we were fine.

And that’s with a 4 year old who wouldn’t be affected by the seat heaters. I can’t speak to any other manufacturer’s implementation but this seems pretty good to me from Polestar at least.

 

[Zoidz]

Residential heat pumps typically have a resistive heating element in order to supplement the heat pump in lower temperatures. I'm wondering if your vehicles have the same feature, and the resistive heating kicks in, making it seem as if the heat pump is sufficiently supplying hot air?

I was thinking the same. A quick Google search (for what that is worth) indicates that there appears to be no auxillary resistive heating element on the Tesla heat pump.

As discussed, heat pumps become more inefficient as temperature drops, most people know that. Also, which may be lesser known, is that heat pump condenser coils can freeze up in cold weather fairly easily. That's because as it removes heat from the cold air, the water vapor in the air flash freezes on the condenser coil. This has reportedly been a problem reported by some Tesla owners. Some residential heat pumps have a defrost cycle with a separate resistive heater on the coil to melt this ice in climates where this can happen.

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