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I have read several posts about a heat pump (or lack thereof). What's the big benefit of a heat pump? Pure ignorance here, not trying to start a war. :) Does a heat pump heat better or use less electric power or ??? I just don't get it. Thanks (in advance) for the enlightenment!
 

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I have read several posts about a heat pump (or lack thereof). What's the big benefit of a heat pump? Pure ignorance here, not trying to start a war. :) Does a heat pump heat better or use less electric power or ??? I just don't get it. Thanks (in advance) for the enlightenment!
A heat pump consumes less power to provide the same amount of heat compared to an electric heat strip heater...so the winter range would be less impacted when heater was in use. The amount of difference is what's still not certain, although there were ongoing tests this weekend using ID.3 cars (one with heat pump, one with strip heater) by Chris on BatteryLife to help compare.
 

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A heat pump isn't involved in heat generation, rather it's role is heat transfer from one place to another and as corfam mentioned less energy (1/3rd the amount roughly) is used to transfer the same amount of heat. In cold weather it transfers heat into the cabin and hot weather it transfers heat out but it's mostly mentioned wrt cold weather because the energy hit there is higher. And in EVs the battery is a heat source which can be utilized.
 

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I have read several posts about a heat pump (or lack thereof). What's the big benefit of a heat pump? Pure ignorance here, not trying to start a war. :) Does a heat pump heat better or use less electric power or ??? I just don't get it. Thanks (in advance) for the enlightenment!
In lamens terms because I’m not as smart as these other guys!😂 You probably will get 10-20% more battery life in the winter with the heat pump.
 

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In cold weather it transfers heat into the cabin and hot weather it transfers heat out but it's mostly mentioned wrt cold weather because the energy hit there is higher.
You probably know this, but a heat pump won't make a difference with cooling because automotive air conditioners already are heat pumps, we just don't usually call them that. The term "heat pump" is usually used when we want the heat and other terms are used when we're discarding the heat, but either way it's the exact same process. Also, heat pumps are typically bi-directional, so they can both heat and cool, but that's not necessarily so.

To further clarify for the original poster... in internal combustion cars, we take advantage of their inefficiency to provide cabin heat. Ideally, we'd like all of the energy in a gallon of gas to go towards propelling the car forward, but that's just not possible. By their nature, every IC engine is going to generate a lot of waste heat that we need to get rid of somehow. In cold weather, we use some of that waste heat to warm the interior, making it effectively free. In an EV, we don't have (much) waste heat, so until recently most EVs just use some energy from the battery pack to heat a coil and blow air over it, just like an electric space heater. Electric space heaters have the advantage that they're essentially 100% efficient - all of that electrical energy is converted into heat. That sounds great until you realize that, measured in the same way, heat pumps are more than 100% efficient - often much more. As Vwvkk mentions, heat pumps move heat rather than generating it directly from electricity, which means that they can pump more heat energy into the car's interior than they expend doing the pumping.

The complicating factor is that heat pumps need heat to pump. As the outside air temperature goes down, heat pumps get less and less efficient. And each system will have a temperature below which it won't function at all. VW has said that their system works to a lower temperature than most, but it still has its limits. As the outside air temperature approaches that limit, a heat pump system will need to add in heat from another source (in a car, that would be the "space heater" style heat). This is why heat pumps are not typically used for residential heating in particularly cold climates (other than ground-source heat pumps, but they're a whole other thing). In those areas, you might find some homes with heat pumps that get a good workout cooling during the summer, but in terms of heating, they only get used in the spring and fall, when temperatures are cool but not cold. In the dead of winter, another heat source is required.

In an EV, adding a heat pump is not the slam dunk some make it out to be. In very hot or very cold climates, it doesn't make much sense to add the weight, cost, and complexity of a heat pump (it's worth noting that prior to the Model Y, no Tesla had a heat pump, either). My personal feeling is that the vast majority of the US is in the Goldilocks zone that's "just right" for an automotive heat pump, but VW seems to think otherwise. These decisions are never as simple as they seem from the outside. For all we know, they're supply-constrained on some part of the heat pump system. And even if adding a heat pump is the "right" decision, it's not really a feature you can sell to anyone but nerdy car geeks. You can sell additional range, but it's hard to sell "maybe some additional range during the colder months, but not if it's too cold." The solution would be to bundle it into a package with a bunch of other stuff, but I honestly think the Statement package is already pushing it at $4,500. They'll probably have a little more pricing flexibility when Chattanooga production starts in 2022; maybe we'll get a heat pump then!
 

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You probably know this, but a heat pump won't make a difference with cooling because automotive air conditioners already are heat pumps, we just don't usually call them that. The term "heat pump" is usually used when we want the heat and other terms are used when we're discarding the heat, but either way it's the exact same process. Also, heat pumps are typically bi-directional, so they can both heat and cool, but that's not necessarily so.
I actually didn’t, so thanks for the clarification.
 

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I actually didn’t, so thanks for the clarification.
I should add that it's entirely possible that Volkswagen's heat pump design has advantages over their normal air conditioner even for cooling, but if so that's not because of any inherent difference in the underlying technology, as is the case with heating.
 
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The deciding factor for the minimum temperature a heat pump can operate at and still provide useful heat transfer is the refrigerant. In the olden days when heat pumps were first used in housing the refrigerant was R12, and then R22 and the useful minimum outside temp was around 45-50 degrees. When those refrigerants were deemed too damaging to the ozone layer, a newer class of refrigerant (which all later model cars use) dropped that into the 30's. The newest refrigerant is CO2 and it's minimum is even lower. Each change in refrigerant increased internal pressures and consequently system costs. A 4-way valve, which is needed to make an air conditioner become a heater and pump heat in the opposite direction, operates at the new much higher internal pressures; is not cheap and the primary supplier of these to VW (and a lot of other car manufacturers) is currently supply-limited.
 

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The newest refrigerant is CO2 and it's minimum is even lower. Each change in refrigerant increased internal pressures and consequently system costs. A 4-way valve, which is needed to make an air conditioner become a heater and pump heat in the opposite direction, operates at the new much higher internal pressures; is not cheap and the primary supplier of these to VW (and a lot of other car manufacturers) is currently supply-limited.
CO2 as a refrigerant has been in use since the1920's, but has been avoided in all but commercial operations due to the higher pressures/costs associated with it.
 

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I should have said "CO2 is the newest refrigerant in use in cars". I'm old enough to remember ice plants that used ammonia.
 

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The ID.3 HP vs no HP tests showed a range improvement of 35km over a 170km test run, if I remember correctly. BUT cost of HP was so high that it would take a long time to pay off the difference in 'fuel' use.
 

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OK, thanks for all the info. Bottom line (for me) is it's not really something I need to be concerned with. I live in southern California - we don't do winter. :)
Correct.

Great discussion, I appreciate the insight everyone brought to it! I hope folks will reference this thread when the pros and cons of heat pumps come up again and again.
To me, the heat pump issue has been overblown. Tesla hasn't had a heat pump until this year and has been quite successful, even in cold Canadian winters.
 
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I think the reason heat pump vs. no heat pump is such a hot topic is because there’s a perceived giant increase in cold weather range. Reality is, the increase is in general notable if not significant. I’m not concerned at all and fully expect that the ID.4 will have a very meaningful, but manageable, drop in cold weather range just like every other EV out there, heat pump equipped EV’s included.
 

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Based on the ID.3 HP vs no HP comparison, there was a 31% difference in range. If you are in a cold climate and are range challenged between charging stations, then that could be the difference between making it or not. I live in a cold climate but I will not be range challenged as the longest trip I see will be a 150 mile round trip. Otherwise it will be short trips around town. It would be nice to have the HP to be as energy efficient as possible, that is part of the premise of these cars. Especially if VW didn't charge what is reported to be stupid money for it.
 

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Based on the ID.3 HP vs no HP comparison, there was a 31% difference in range. If you are in a cold climate and are range challenged between charging stations, then that could be the difference between making it or not. I live in a cold climate but I will not be range challenged as the longest trip I see will be a 150 mile round trip. Otherwise it will be short trips around town. It would be nice to have the HP to be as energy efficient as possible, that is part of the premise of these cars. Especially if VW didn't charge what is reported to be stupid money for it.
There were a lot of odd numbers in that video (assuming you're talking about the Battery Life one posted today). Charging and energy consumption (Wh/km) both seemed in the range of only 7-9%, decrease in state of charge looked like an 18% hit for battery, and range estimate was ~31% as you say. I would have hoped for some more definitive numbers, but with the numbers presented, I'm not comfortable drawing conclusions.

The range estimate seems the most likely to be off, but it seems like the consumption rate, final charge required, and SOC should all be more closely aligned than the values they found of 7, 9, and 18%, respectively. If the difference is closer to 7-9%, that seems more acceptable in terms of the decision to leave out the heat pump, but it's harder for me to explain the inconsistency and the higher potential comparisons of 18% and 31% loss for resistive heating.

Edit: Clarified the range % difference in post 19 below.
 

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I think the reason heat pump vs. no heat pump is such a hot topic is because there’s a perceived giant increase in cold weather range. Reality is, the increase is in general notable if not significant. I’m not concerned at all and fully expect that the ID.4 will have a very meaningful, but manageable, drop in cold weather range just like every other EV out there, heat pump equipped EV’s included.
The main benefit of the heat pump is reducing the HVAC power consumption by ~3x. Relative to the total power consumption, that will mainly make a significant difference if:
1. One does long distance driving in cold conditions
2. Charging options en route or at destination are limited.

Since one of my primary uses of an EV is traveling to cold mountainous regions, the lack of a heat pump only amplifies the range loss. I'm willing to pay more to improve the efficiency of the existing vehicle. What I find most irritating though is the fact that the US is the only market in the entire world that VW does not let the ID4 have a heat pump as an option. They've even gone backwards relative to their previous EV, the e-Golf, as even that car had a heat pump in the US. At a minimum, the US market deserves an equivalent vehicle to the rest of the world. Just like any other car, you should be able to choose and pay for the features that are important to you.
 

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I think in the end it really would be smart if post factory installation of a Heat Pump was an option. Let the buyers that really need it, get it. I'm another SoCaler and while I have no need for a heat pump I do love trying to get my hybrid to be as efficient as possible from time to time. I consider it a game.
 
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Based on the ID.3 HP vs no HP comparison, there was a 31% difference in range. If you are in a cold climate and are range challenged between charging stations, then that could be the difference between making it or not. I live in a cold climate but I will not be range challenged as the longest trip I see will be a 150 mile round trip. Otherwise it will be short trips around town. It would be nice to have the HP to be as energy efficient as possible, that is part of the premise of these cars. Especially if VW didn't charge what is reported to be stupid money for it.
Upon further review, the 31% difference is range remaining. It's difficult to know what the actual range difference was, because they started at 80% charge and reset odometers 16-20 km in, but even for just the saved 144 km driven, the non-heat pump had only 13% less combined (actual + projected) range. [144 km + 69 = 213 vs 144 + 101 = 245]. Accounting for an additional 20km pre-reset, it's only a 12% difference. So this is much more in line with the % difference from SOC, required charge, and consumption rate.

Still not a scientific study, and it's only 1 data point, but it starts to look like heat pump vs resistive heating might be a real world difference somewhere around 10-15%.
 

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I was initially more concerned about the heat pump before we had real world numbers. Although there’s no hard study yet, I feel much more comfortable now getting the Id.4 without a heat pump especially since it will mostly be used for a low mileage commute. I still wouldn’t use it for driving out to go skiing and other winter outings in the boonies where chargers are not found easily since I have a 2nd ICE vehicle for that and if it was my only vehicle it would give me pause. Whenever I update our 2nd vehicle which is some years out I’m hoping range and efficiency will maximized for that So it can be a longer range winter driver in all conditions. I expect range and efficiency in EVs to be much higher on the average 5 years from now. The technology is improving rapidly. But the Id.4 can be a great summer recreation vehicle and an all a year round commuter.
 
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