When I put the heater on, the windows steam up like crazy, there is a warm musty smell coming from the vents.
It is not put to recirculated air. Only opening the windows and turing heater off clears the mist on windows.
Any ideas what can be done to stop this?

Neil Armstrong, March 2010

my astra window are steaming up like mad too. any ideas why its doing this suddenly?

007, February 2011

So its more than likely moisture inside the cabin and not some fault with the heating system itself?

Neil, March 2010

There may be moisture in the car - in the seat fabric and in the carpets etc. - ventilate it as much as you can and allow the mosture to evaporate. The warmed air is absorbing the moisture and the blower is spreading it around the interior.

Only garage the car when it's had a chance to cool down. If you can park it up for a couple of hours with all the doors open. Drive around with the windows open if you can stand it

Buzz Aldrin, March 2010

try running the airconditioner with the heater on,it will dehumidify the air.It will still be warm.

charlie, March 2010