Is cabin heat "free" if a Prime is in HV mode?

In the Gen 4 PHEV in HEV mode, you can turn off the heat pump by using the A/C button and keep only the fan running, which will utilize the engine-coolant heater core to warm the cabin. In fact, even with the fan off, you can still feel heat coming from the vents.

I don’t see why this should be impossible in the Gen 5 PHEV, but then they added refrigerant battery cooling, which could lead many Gen 5 PHEVs to the junkyard once the battery warranty expires, since repairs would be very costly. The Gen 6 RAV4 PHEV already uses engine coolant to cool the battery, so this refrigerant cooling system will remain unique to the Gen 5 Prius PHEV.

 

The current Rav4 plug ins also use refrigerant cooling. Other Toyota EVs might also use it, or use the AC to chill the blown air.