An MPG tip for your car: Use defrost sparingly.

[Eleanors38]

7. Thanks. Another benefit of using non-AC/hot coolant heat

I forgot to mention: Your heater "core," the small radiator-type unit forced-air passes through, will have its life extended by frequent circulation or flushing through it (engine waterpump); otherwise, the coolant & other materials remains stagnant in it resulting in corrosion, then leaks.

My old '63 Chevy Nova's heater core lasted for 28 yrs: the design had engine coolant ALWAYS running through it, and you controlled temp by moving via cable control a trapdoor panel that allowed more or less outside air to mingle with the hot air; when off, the panel directed all the hot air outside! Primitive, but effective.