We have tested a dust filter that combines the best features of plastic and nylon filters. It has high mechanical resistance, is easy to clean and yet also has low restrictiveness, so it does not significantly change the sound of the fan and does not increase its noise level. Compared to plastic filters, it does not even “hiss”. This addition thus extends the database of results with the latest type of dust filter, one with a metal grille.
More air, less noise
If you have a plastic filter in your case, then beware – replacing it with a metal one makes pretty good sense. A plastic filter reduces the flow very significantly, and also noticeably increases the noise level. The Akasa metal filter is even better at this than nylon filters.
Compared to nylon, metal has the upper hand at low speeds (i.e. typical system fan speeds) and the airflow through it is 9% higher. In this, the plastic filter with a similarly thick mesh does not hold a candle to the metal one, and at a higher overall noise level it has only around half the flow rate (23,3 m3/h versus 39 m3/h). This is an excellent testimonial for the metal dust filter.
At higher (and rather high) speeds, the nylon filter restricts the fans less, but we don’t care about that so much, because in practice the speed of the system fans is always low. And with them, more air flows through the metal filter at lower noise levels.
Compared to plastic filters, the sound does not even contain hiss at higher frequencies, at which it is virtually noiseless. One could even say that the character of the sound of a fan without an obstacle does not degrade. Slightly higher mechanical resistance is produced, though, and dBA values are higher at the output, but note the three peaks in the spectrographs in the 100-500 Hz band. With one, more intense (which is typically the situation with a hexagonal grille), the sound is considerably sharper. It’s a wonder Akasa hasn’t built marketing around it. Although it is true that these filters are sold for single digit sums of euro, which are such small price points that from a business point of view, it is almost pointless to bother with them.
In terms of dust collection efficiency, Akasa’s metal filters won’t be any more efficient due to the rougher mesh, but compared to plastic filters, it’s a whole different class altogether. The flow is throttled significantly less, and at a lower final noise level alongside a more pleasant sound.
Compared to a plastic filter, this metal one has perhaps no functional disadvantage. If you can think of any, we would be happy if you share it in the comments. Maybe there is something within a specific application. Maintenance is on par and they are easy to clean and strong. Keeping the shape stable is an even better advantage over nylon filters, which collide with some fans due to the fluting of the mesh. With those having a small height difference between the rotor and the frame. Metal filters will not disable such fans.
The prices of Akasa metal filters are affordable and range from 1.50–3.50 EUR depending on the size. You can find them in stores as GRM120-AL01-BK (tested model for 120 mm fans), GRM140-AL01-BK (140 mm), GRM92-AL01-BK (92 mm) and GRM80-AL01-BK (80 mm).
TL;DR: Compared to plastic filters, the tested GRM120-AL01-BK metal filter is a better alternative in all respects – higher airflow at lower noise level, while the amount of dust retained is similar. In this regard, a nylon filter remains a more effective solution due to the finer mesh.
English translation and edit by Jozef Dudáš
