I think the use of hot water heating also keeps the cabin temperature from varying as much as might happen with a direct electric element to air heating design.tesla500 wrote:Why did Nissan choose to use hot water based cabin heating? It seems to make much more sense to heat the air directly, and avoid wasting energy and time heating up the thermal mass of all that water.
My Pontiac Firefly electric conversion uses a 1.5kW ceramic direct-to-air heater, which is hot 10 seconds after turning the car on. The LEAF is a downgrade for me in this respect!
When I look at the climate control system energy use on the nav panel, it looks like maximum heating energy use may go as high as 4 kW. If the direct heating coil was using that much energy and the fan failed, the heating element would probably get very hot in just a couple of seconds, even if a thermal safety switch was installed in the system. Might result in a melted heat chamber, or even a fire. Wouldn't want to have that if the car was unoccupied, preheating in the garage.
They also tend to smell when they are first turned on, particularly if dust has collected on the coils.