Ventilation heat transfer

[hdp160]

I have a naturally very warm room below (and one metre offset) a naturally cold bathroom.
I've lifted the floorboards and there is an clear simple route between the two rooms.
Does anyone have any ideas regarding transfering some of the warm air to the bathroom .... Either forced or by simple heat rise principles.

 

[stem]

It's probably not a good idea, if you introduce air into the bathroom the same volume of air will be forced to exit the bathroom, so damp air / steam and er.... odours will then travel throughout your home.

The professional way to do it would be by using a heat exchanger to keep the air flows in the two room separate, but they are expensive.

 

[hdp160]

Interesting, I will have to think this through