thanks sillypup for the shoji screen idea.
and thanks Gabriela for the answers. I'll try doing the joss stick to test out the air flow (i didn't know that we could use this to test air flow).
For the time being, I will put up mirrors first and do the joss stick test.
So far, the whole house has been doing much better now since i've done some fengshui (it has more balanced elements now, before it was too much metal). I've also done some de-cluttering throwing some old stuffs that no longer do me any good (it was sad to part with them but it makes the whole house feels "lighter"). My and my partner "luck" also seems to improve since we create more spaces on the front hallway by moving our shoes wardrobe somewhere else.
I'll do the fengshui change bit by bit everyday.
Thanks for your help.