Eli5: If I get in a cold car and want the temperature inside to be 71, so I set it for 71 or set it higher until I am uncomfortable?

Question

What is the fastest way to heat the inside of a car or room. Set the heater to desired temperature or initially set it higher than wanted?

In: Engineering

Answer 1

assuming the engine or room are both cold to start, just choose 71º. room heat blows at one v high temp so speed is not controllable. it turns on & off to hold 71º. a cold engine must reach a temp able to blow 71º air into the cabin. once the cabin reaches 71º throughout, the air continues but temp stabilizes at 71º.

engine hot/cabin cold: blowing 90º air speeds up how fast the cabin temp reaches 71º but it will continue increasing to 90º unless lowered to 71º.