Deoc wrote:The heat pump has its limits, below 35-30F the heat pump can't get more heat from the outside so the resistance heater has to work, this one is inside the car and doesnt use any liquids on the 2013 and up models, so blocking the grill doesnt do anything,
Yes, at a certain temperature the heat pump stops working and it goes to resistance heat. But it's closer to 5*F-10*F when I've noticed it go from heat pump to resistance heat in my 2013 SL. And even then, the outside temperature isn't likely going to stay at such freezing temperatures all winter long. Some days are warmer than others. Even here where I've driven my Leaf in -35*F weather one day in a week it can be 40*F. It seems to me that it's better to keep air flow to the heat exchangers because of this. After all, this isn't an ICE that needs to be kept at boiling temperatures with it's own heat. Instead we're trying to heat up a freezing cold heat exchanger with no noteworthy source of heat except cold ambient air.
LeftieBiker wrote:You seem to be thinking that the grille block seals the motor compartment. That doesn't happen. People have run the A/C with one in place. It just reduces airflow.
That's the point. It reduces air flow. You don't want to reduce air flow over a heat exchanger. This I know. After all, I own a 1972 air cooled VW Beetle. The more air that flows through it the more heat is exchanged. The less air that flows through it the less heat is exchanged. The less heat is exchanged the less efficient it is. The less efficient it is, more energy is used.