Topic: Best window defogger spray?

[Zychro Pierce]

My back window always accumulates fog and in the colder months, the window is frosted over from the inside. I hate having to scrape it all from inside. Anyone know any good window sprays to prevent it from forming?

[Railton]

My back window always accumulates fog and in the colder months, the window is frosted over from the inside. I hate having to scrape it all from inside. Anyone know any good window sprays to prevent it from forming?

The back window (any of the windows really) is frosted over from the inside due to moisture inside the vehicle - like wet mats and anything else holding moisture. Eliminate the wetness and it will clear up your problem.
Railton

[Slow_lane]

Check and see if you have your ventilation system on recirculate. This keeps moist air inside car instead of bringing fresh air in. A simple push of this button may resolve your issues.

So many people screw this up.

[Ex-airbalancer]

Check and see if you have your ventilation system on recirculate. This keeps moist air inside car instead of bringing fresh air in. A simple push of this button may resolve your issues.

So many people screw this up.

Most  vehicles I have seen will automatically default to 100% outside once you place the HVAC system to defrost

also you should never call outside air, fresh air, because if you are by a sewage treatment plants , some farms, or a highway the air may not be very fresh 

[UnknownJinX]

There are those RainX sprays, but they don't have very good reviews. People say that they are hard to apply and if you mess up, it will look like there is a light haze over your window.

What I find is that if your windows fog up easily, you should clean your car windows. Really helps.

Also, you can use the AC to remove moisture in your car. An AC also functions as a bit of a dehumidifier.

[Noto]

^^ agree.

Costco sells the Invisible Clear Glass:

http://www.canadiantire.ca/en/pdp/invisible-glass-aerosol-0390432p.html

...in a 4-pack for $15 (much cheaper than CT).  The stuff works really well to clean the glass.  Once clean, try to keep moisture out of the interior of the car, and use the defogger (front and back) as necessary.