they work, but the thing is if you opened the case and it was "covered" in dust, then the filters would prolly get cover quite quickly, and eventually change if not completely stop the amount of airflow going through your case, my advice, dust your computer once every 3 - 6 months and dont worry about it, thats just a waste of money and the filters will just collect all the dust and stop your fans
Thanks for the info, last thing i want is a hot case. I've got a graphics card that may not like me too much. I'll stick to compressed air aerosols (assuming they're any better...?)
thats the purpose of the fan filter.....to collect dust. i have 4 fans, all have filters ,never have problem with it, filters do minimize airflow and also dust buildup, id rather be cleaning my filter than my whole system every now and then.
Of course you could take the radical approach and seal your entire motherboard and components and then rinse it in rubbing alcohol/water ... or run the computer in a submerssed environment