Ethernet Cable And Cold Is It Safe To Fish Cat-6 (ethernet) & A Coax (T.V.) Cable Through My Vents?

Is it safe to fish cat-6 (ethernet) & a coax (T.V.) cable through my vents? - ethernet cable and cold

I try to fish with two Ethernet cables (and coaxial) from the basement into a bedroom, and I wonder whether it is acceptable to go through my heating / cooling ventilation? (I have tried to go with him, but never arrived at the other end, so failz @ fish)

I know this is not the code, but I'll put a lot of problems, so I want to know just hot air injury / cold for the wiring of all / my internet so slow? I just want to know whether to do it right.

Thank you!