Heat Pump vs Seat Heater

[GaRailroader]

Has anyone made a determination as to whether it is more efficient to use a single seat heater or the heat pump powered cabin heat? In my Tesla I always use the seat heater but it doesn't have a heat pump like the Leaf.

 

[knightmb]

Has anyone made a determination as to whether it is more efficient to use a single seat heater or the heat pump powered cabin heat? In my Tesla I always use the seat heater but it doesn't have a heat pump like the Leaf.

As good as the heat pump is in the Leaf, the seat heater uses a whole lot less power. It's warming your butt/back vs. warming the entire cabin. If you are comfortable with the cabin temperature, the seat heater will always win as the power usage is so tiny.

I happen to be messing with my Leaf (when am I not :lol: ), so I measured the power usage of the seat heater on Low and High. On Low, it uses about 13 watts, on High it is using about 50 watts. The heat pump, at it's lowest setting is still using 250 watts (not including the power that the radiator fans are using while running and the cabin fan to blow the air around inside), but that would mean you probably have the Heat set really low, like 65F or lower. I usually set my temperature for 68F on Auto, during the night I use fresh air to keep the windows from fogging up, during the day I use re-circulate if the humidity is not too high. The steering wheel heater uses the same amount of power as the seat heater on high, if you want some additional heat.

 

[GaRailroader]

knightmb: Thank you for the very detailed response. When riding alone I'll continue to just use the seat heater and leave the cabin heat off.

 

[LeftieBiker]

If you want a middle ground: Eco, heat, lowest fan speed, temp set to 65F, vent set to floor or floor + defrost, Recirculate on Auto/Partial.

 

[SageBrush]

If you want a middle ground: Eco, heat, lowest fan speed, temp set to 65F, vent set to floor or floor + defrost, Recirculate on Auto/Partial.

What is the power draw ?

 

[user 24513]

If you want a middle ground: Eco, heat, lowest fan speed, temp set to 65F, vent set to floor or floor + defrost, Recirculate on Auto/Partial.

The only part of this well-formulated response that I question is the "lowest fan speed", the fan itself uses minimal energy and it seems like it spreads the small amount of heat being generated around the cabin better at slightly higher speeds... ALL MMV!

 

[user 24513]

What is the power draw ?

Since it is illegal to actually watch LeafSpy while driving, my replies will be speculative at best, but I speculate that using Eco, feet and defrost, maybe 65 degrees, mid-level fan, partial recirc, the useage can be as high as 3500 watts in cold weather to as low as about 1000 watts once the car is warmer- the average being maybe 1750 watts at 20 degrees F?

 

[user 24513]

PS I should point out that my Leaf is an S+ and therefore does not have the heat pump... certainly a mistake but also possibly the cheaper option over the years since it cost a bunch less....

 

[LeftieBiker]

If you want a middle ground: Eco, heat, lowest fan speed, temp set to 65F, vent set to floor or floor + defrost, Recirculate on Auto/Partial.

The only part of this well-formulated response that I question is the "lowest fan speed", the fan itself uses minimal energy and it seems like it spreads the small amount of heat being generated around the cabin better at slightly higher speeds... ALL MMV!

It depends on the humidity. If the windshield isn't fogging, then Low is the best bet. If there is fogging, then 2 is better. 1 with the recirculate off also works pretty well if there is real fogging. (I would have added that when I posted, but my cat was in my arms, and I was typing with just my left index finger.) As for the power draw: I don't know the exact figure, but I remember using this combination on a frigid drive home (about 13F) in which I was worried about range, and was watching the % meter like a hawk. On that setting combo, the car was using power, according to how fast the % fell, at nearly the same rate as with the heat Off. This was a Gen 1.5 Leaf with heat pump.

 

[SageBrush]

If you want a middle ground: Eco, heat, lowest fan speed, temp set to 65F, vent set to floor or floor + defrost, Recirculate on Auto/Partial.

The only part of this well-formulated response that I question is the "lowest fan speed", the fan itself uses minimal energy and it seems like it spreads the small amount of heat being generated around the cabin better at slightly higher speeds... ALL MMV!

I watched LeafSpy a few weeks ago on a cold morning of 10F while I was charging. The power consumption correlated with fan speed. Like you, I didn't expect that to be the case.

 

[LeftieBiker]

The reason for power consumption shooting up with fan speeds is that the heater(s) are not controlled by an On/Off switch, but by a controller that varies heater current with fan speed (among other things). The engineers wanted to keep the air flowing outward from the heat exchanger from getting too hot, so the output is lower with the lowest fan speed, and increases in increments. That's why I recommend only fan speeds 1 & 2 when trying to minimize heater draw.