[quote=FL07THC;100195]The heat in your car is pulled out of the engine. The heater core to be exact. Your antifreeze has to be up to temp for your heater to work.
There is also a supplementary electric heater it's called a PTC heater, here is Toyota's description of it:-
"The PTC heater is installed in the radiator in the heater unit and operates when cooling water temperature is low and normal heater effectiveness is insufficient.
The air conditioning amplifier switches the circuit in the PTC relay and operates the PTC heater when the operating conditions (cooling water temperature is below 55°C (131°F), setting temperature is MAX. HOT, air outlet damper position is FOOT or FOOT/DEF, and blower switch is not OFF) are met.".
Here is more detailed information and a drawing:-
From this information is appears you should get more or less instant heat similar to turning on a hairdryer, although I can't say I've really noticed it!