This is great news! We typically lose about 30% range in winter. Are you suggesting with the heat pump, the loss would be only 15%-20% on the same drive? Living in Manitoba, we are wondering about the value of a future upgrade to a new M3 with the heat pump.
I wouldn’t get excited. I think you’ll see great efficiency out of the heat pump down to about 30F, but below that you’re going to be closer to a COP of 1 (resistance heating). [Ok, realistically the unit might have a COP of 1.5 to 1.8 around that temp, but because of the size of the system it likely won’t be able to supply the amount of heat to quickly warm the cabin just from collecting heat in the air so it’ll pull electricity from the pack to supplement] Heat pumps aren’t magic, there has to be sufficient heat in the air for it to concentrate and pump into the cabin, just like home heat pumps; most people have backup electric coils that run in very low temps (sub 30F). If you look at any chart of a home heat pump the BTU output usually is 50% of it’s rated amount down to maybe ~30% once outdoor temperatures are down to 20 to 30F.
Now the Tesla system is a little more than just a heat pump. The system also connects all the electronics into the same heating loop. If the motors, battery, or inverter has waste heat from usage than the will get pumped away by the heat pump and added to the cabin. I think on “short” [maybe less than 30 miles) drives you won’t notice much of a difference since the battery will still be warming up and the motors and other electronics don’t produce THAT must extra heat, otherwise they wouldn’t be so efficient. In addition, low speed drives with a lot of sitting in traffic won’t be able to scavenge much heat from the motors since they won’t be running while not moving. Expect the heating system to operate approximately the same as the older Model 3 system.
Now potentially on very long highway trips (75+ miles) the battery and electronics may get to a steady temperature that the heat pump is able to pull some heat from them and add it into the cabin. This is essentially free heat (you already used the energy for movement and heat was left over) so that will greatly improved the efficiency of the heating system.
Also, the battery gets warm from charging, so if you usually need to do a fairly substantial charge every day (say 25%+) if you can do that RIGHT before you leave, you’ll have “stored” heat in the battery as a byproduct of charging (the energy came from your wall) which is “free” heat for the cabin. But if you complete the charge at 2am and don’t depart till 8am, you won’t see this gain.
If you usually charge the moment you get home at 6pm and the charge is done by 8pm and you leave every morning at 7am for your 5 miles to work... don’t expect much or any improvement when temperatures drop to 30F or below. If you used 350 Wh/mi for the 5 miles to work (1.7kWh) in the 3 with resistance heating, don’t expect to suddenly use 245 Wh/mi (1.2kWh) with the heat pump.
Don’t get me wrong, it is an AMAZING system and engineered really well, but it isn’t magic. The fact is there isn’t a giant inefficient part of the car that just spews out wasted energy as heat, so the car barely has any heat to collect other than from the air. On long drives to maintain the loss of heat from the cabin to the outside the heat pump capacity might be able to keep up just from pulling from the air and might be COP of 1.5 to 1.8 (1kW in produces 1.5 to 1.8 kW worth of heat) but on shorter drives where you have to warm all that air up to a comfortable temp, expect about the same as the resistance heater.
