You either just need to wait for it to heat up when the car turns on, or it's broken.
A car heater taps off engine heat. If you aren't driving, then the engine is cold and there's no heat for the car heater to use.
Low coolant and a clogged heater core are possibilities.
faulty control valve on heater or air in the lines
You need to change your thermostat in the car.
open or missing thermostat
No
A block heater is a device one would use to heat the engine of a car in extremely cold weather. The block heater can be mains generated or will run on the fuel source of your vehicle.
Is an electrical device used to heat coolant of a vehicle at extreme cold condition for easy startup.
AnswerBad thermostat, clogged heater core, or a defective heater control switch. If an engine has not been running long it will not have warmed up, the warmth from a car heater usually comes from the engine.
The #1 cause of cold air from the heater when the car is stopped, or the engine is idling, low engine coolant levels.
Low on coolant, stuck open thermostat, plugged heater core, faulty temperature blend door,
How long it takes a car heater to warm up depends on the temperature outside. In cold weather the heater can take several minutes to warm up.