The best way to get the heat going is to get the car on the road. The heat from the engine will soon have you toasty warm.
Using the air conditioning, even during winter, will help you reduce the fog that can accumulate on the inside of your windows. Your car’s air conditioning is a dehumidifier, which is why it can help with window fog and visibility. You can actually put the air on and leave it, because when the temp is below freezing, the compressor will shut off automatically. As you can imagine, the air conditioner doesn’t have to work very hard in the dead of winter and will really save you headaches from window fog. It’s definitely worth the minimal amount of extra gas and engine strain it will take to run the air.
Using ‘recirculation mode’ just circulates all the air that’s in the cabin, which will also cause fogging. It gets worse with each exhale, so get some fresh air in there.
The other thing that’s annoying when you have passengers in the car is being a Scrooge on the heat! Since the heat in your car comes from heat generated by your engine, it’s free, unlike air conditioning. So skimping on heat doesn’t save you gas or money; it just makes you cold and might get you visits from the Ghost of Christmas Present, not to mention gifts of coal from your passengers.