You need to have a good flow of air through your PC to try to keep the components cool, so its best to have a fan at the front to suck air in and a fan at the back to blow it out.
I think the standard size fan in most PC's is 80mm but if you have space for a larger fan then thats better as you can run it slower for the same amount of air flow - slower fans will generally make less noise.
Dust will always be a problem in this country but you can try some AC dust filter which if you have space you can fit to the front of your PC between the metal case and the front panel but depends on the design of your case.
Also good to have adjustable speed fans or fan speed controllers so that you can turn down the speed of the fans to decrease the fan noise.
You need to have a good flow of air through your PC to try to keep the components cool, so its best to have a fan at the front to suck air in and a fan at the back to blow it out.
I think the standard size fan in most PC's is 80mm but if you have space for a larger fan then thats better as you can run it slower for the same amount of air flow - slower fans will generally make less noise.
Dust will always be a problem in this country but you can try some AC dust filter which if you have space you can fit to the front of your PC between the metal case and the front panel but depends on the design of your case.
Also good to have adjustable speed fans or fan speed controllers so that you can turn down the speed of the fans to decrease the fan noise.