Anti-defogging/defrosting units work fine. Just wait a few minutes. You don't need an extra set of wipers INSIDE the window. You'd have to hide the wipers, might need another motor, the condensation inside the car disappears quickly and you don't need the added cost.
If it ain't broken, don't fix it!
You don't get "fogging up" if you know how to use your climate control! When people breathe in a vehicle it ups the humidity. Usually people have their fresh air control set to recirculate which keeps fresh less humid air from getting into the passenger area. You need to set the air intake to fresh air. If it's a bigger problem you then turn the AC on which can also be run while the heater is on. That takes the humidity out of the air. A leaking heater core also fogs up a windshield. Make sure the floor is dry.
WWII pilots used to polish soap on the inside of the canopy to prevent fog, the defroster on a modern car uses the A/C system to dry the air so the fog is removed. Fog is a condensation thing. If you use the A/C to defog the inside of the windshield, the outside of the windshield starts to condense water. I guess this is a catch 22 defog question, have a great day :)
I usually just put the heating system on a cool setting a drop the window slightly to get some air circulating, works for me - I would like a Christmas tree on the dash though
Well the dashboard fan is there for a reason. You push the button, it blows the fog and drys it off and turn it off again if you want.
I never user windscreen wipers .My friends experience is ****.
Disadvantages?
