Demisting Windscreens

[nextphase]

I've had cause to do quite a bit of driving in DH's car, and am getting annoyed by the fact that the windscreen keeps misting up while driving.
I keep the fan on, partly on the windscreen, but still had to wipe it with a cloth to demist while driving today.
DH cleans the inside of his windscreen with window cleaner. Could this be the cause (doesn't happen in my car!)?
Any ideas on how to lessen the fogging?
Cheers

have a look at the heater settings. Quite likely it is set to "recirculate" rather than "fresh air"

that means the moisture content of the car, including that constantly added from breathing and perspiration, increases and is not ventilated away.

On rainy days you sometimes see cars whose windows are streaming with water because the drivers have forgotten this.i

Moisture content will be increased if there is a water leak, typically from rain getting round a window seal, but it has to be pretty bad if blowing fresh air onto the windscreen can't remove it.

If the air con has been on, and you turn it off, then for several minutes the water that has condensed inside it will evaporate off and be blown into the car. The fresh air setting on the heater will blow it away, opening a window will allow it to escape more quickly.