Heat pump vs non heat pump. What is the difference in efficiency

[Oxford]

Good morning to the forum, I have a buddy looking at the 2024 MachE premium, he drove my 2023 and really liked it. The fact that it does not have a heat pump seems to matter or at least one of his questions. So does anyone have any idea as to what the impact is on a heat pump ? Are we talking 10% difference in battery useage, higher or lower??
Second question to this, has anyone heard any rumours that the 2025 will be getting the heat pump like the F150 did for 2024?

Is it worth him waiting for it or take the deals that are out there now? Sometimes you ask the question, is it worth spending $5,000 or $10,000 more for something that will save you maybe $100 a year?

I think this question is definitely down Machlee's alley, but everyone else is welcome to comment.

Thanks

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[Snakebitten]

What part of the country is your friend in?

 

[Oxford]

What part of the country is your friend in?

Southern Ontario, same as myself. he drives about 15,000 km per year, so not a huge amount of miles

 

[grein002]

Having a heat pump in an EV is less about saving money and more about limiting range loss on long trips in cold weather. How much of a difference it makes depends largely on how cold it is. Below a certain temp, it will not make much difference, as heat pumps lose efficiency as temperature drops. I'm just surprised more EVs don't have them, since most of what is needed is already present in the AC system.

 

[Snakebitten]

Southern Ontario, same as myself. he drives about 15,000 km per year, so not a huge amount of miles

I gotta admit that it would matter to me more in Ontario than it does down here on the Gulf Coast.

I had a heat pump in my lowly little 40KWH Nissan Leaf and I gotta admit it would warm up that cabin quickly. And according to the experts, quite efficiently.
However, even if climate control used ZERO KWH of the HV battery, the Leaf couldn't have near the range of a Mach-E without a heat pump. ?

 

[ChehRob]

I have seen reports with a low as only 4% improvements from using a heatpump over resistance heating. I don't know if that is a reliable number.

 

[CTZ]

A heat pump will make a big difference. It just moves heat from the outside instead of creating it. But, like the poster above mentioned, it's really only about the range. If you don't drive more than the range of the car between charges, it not a big deal. I'd probably take 10 to 20% of the range off depending on the temperature.

 

[Thunderbuck]

I drive a Mach-E in the Yukon. A heat pump would definitely be great to have but it's not a dealbreaker.

 

[Oxford]

A heat pump will make a big difference. It just moves heat from the outside instead of creating it. But, like the poster above mentioned, it's really only about the range. If you don't drive more than the range of the car between charges, it not a big deal. I'd probably take 10 to 20% of the range off depending on the temperature.

A good point, range is effected, I noticed about a 20% reduction in range, in the summer I get over 5km/Kw. In the winter it drops down to about 4km/Kw so that effects the economy but not sure if a heat pump could add 10% back. Cost is a factor

 

[Zardoz]

As far as a heat pump, it really depends on what you define as 'cold' for your area. Depending on the heat pump you won't get much (any?) benefit below 15F (-9C). Some heat pumps lose most of the efficiency benefit by 20F to 32F (-7C to 0C). As the temperature drops the heat pump will be putting out warm air, not hot air, and may need to supplement with resistive heating (which means more energy usage than all heat pump). So, at 0F (-18C) the heat pump will be no benefit; at 45F (7C) it will be much better than resistive heating. As it gets colder the heat pump loses efficiency AND the battery loses capacity; the loss of range due to low temperatures will be less at milder temperatures but may fall off more suddenly at a certain low temperature.

There are advanced heat pumps that work in colder temperatures. I'm not sure if they are available in vehicles. These cold climate heat pumps are made by Mitsubishi and maybe others.

 

[B177y]

I have an apple's to oranges comparison, but it might help....

I went from a 2023.5 MME CR1 to a 2024 Lightning Pro (heat pump). I am on the Olympic Peninsula in the NW corner of NW Washington, across the Strait from Victoria Canada. We have had a few cool mornings already so plenty of chances to use the Lightning heat. I had CarScanner set up in the MME and now on the Lightning to watch the heater and air conditioner usage.

The MME would use up to 8kW on the heater when I called for it. The MME heated up very quickly, turn the heat up and it got warm in the cabin, no hesitation. I kept the MME temp pretty consistently at 68 deg F and it was always comfortable. The efficiency hit was obvious while driving as my normal was around 3.2 MPK and if using heat would quickly go into the mid-high 2.x MPK, even lower if it was really cold.

The Lightning doesn't warm up nearly as fast. The heater generally bounces between 0-4 kW and the "air conditioner" (heat pump) spools up and down, but tops at about 9 amps total (it only shows amps in CarScanner for the AC, not sure if it's off the 12 volt or the HVB. If 12 volt, then it's about 110 watts (per @Snakebitten it's 240 volt so that's about 2200 watts)). I adjust the Lightning cabin temperature anywhere from 68 to 76, and usually keep it around 72 to get comfortable. The heat is much slower to come no matter where I adjust it. Efficiency wise, my normal in the Lightning is 2.4 MPK. With the heat blasting, it goes to about 1.8. In normal cruising with it set to 72, I get about 2.2 MPK in cool weather.

Yesterday the kids and I got hit with a cold driving rain that turned into a windy thunderstorm during their soccer practice. After the thunder hit we cancelled practice and got into the Lightning, all cold and wet. I cranked the heat to max, it very slowly got warm. The outside temp showed 46 F. I wish I had the instant MME heat... The Lightning was much more like an ICE vehicle, I had to wait a while for it to heat up. CarScanner showed my air conditioner at 9 amps pretty consistently, and the heater was late to the game, and cycled on and off from 0-4. We waited about 5 minutes while we warmed up and waited for the window fog to clear. I was at "Auto 3 (high)" and heat to "MAX" with the seat heaters on high.

All of this to say that the heat pump is not a godsend, but it's not terrible. I think it is more efficient than the resistance only heater, but not nearly as quick to heat. The lowest outdoor temp that I have driven in so far is 40 deg F, so no real world comparison in really cold temps yet.

 

[Snakebitten]

The Lightning, Mach-E, and Powerboost all have 240V HVAC compressors. And 9 amps at 240V doesn't sound far off of the Powerboost PID that I monitor.

 

[AZBill]

As far as a heat pump, it really depends on what you define as 'cold' for your area. Depending on the heat pump you won't get much (any?) benefit below 15F (-9C). Some heat pumps lose most of the efficiency benefit by 20F to 32F (-7C to 0C). As the temperature drops the heat pump will be putting out warm air, not hot air, and may need to supplement with resistive heating (which means more energy usage than all heat pump). So, at 0F (-18C) the heat pump will be no benefit; at 45F (7C) it will be much better than resistive heating. As it gets colder the heat pump loses efficiency AND the battery loses capacity; the loss of range due to low temperatures will be less at milder temperatures but may fall off more suddenly at a certain low temperature.

There are advanced heat pumps that work in colder temperatures. I'm not sure if they are available in vehicles. These cold climate heat pumps are made by Mitsubishi and maybe others.

You are assuming the heat pump only has access to outside air. GM and Tesla connect the heat pump to motor waste heat, which makes it even more efficient. They only need resistive heating at the beginning of the drive, prior to the motors warming up.

 

[Rory]

See also the posts about the glass roof. In very cold weather, you’ll probably get more range gain from having a solid roof instead of a glass roof than you’d get by adding a heat pump.

 

[Zardoz]

You are assuming the heat pump only has access to outside air. GM and Tesla connect the heat pump to motor waste heat, which makes it even more efficient. They only need resistive heating at the beginning of the drive, prior to the motors warming up.

I had forgotten about that! That is a benefit. I hope the motors aren't warm enough to heat the battery and cabin to comfortable temperatures in sub-zero temperatures, but every little bit helps.

Do new Mach E's harvest some of that motor heat?
https://www.macheforum.com/site/threads/heat-pump-in-new-models.33047/

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