Have to press accelerator in order to warm up the engine

Good afternoon,

It takes the engine run-up to 5 minutes before the heat develops in the car. The colder the weather, the longer it takes for the heat to work.

https://www.2carpros.com/articles/how-a-car-heater-works

Revving the engine does help some but it is not recommended. Check the coolant level to be sure it is correct.

https://www.2carpros.com/articles/car-heater-not-working

Does the engine temperature run normally? A stuck open thermostat would delay the engine in producing heat.

Roy