All DC fan manufacturers use almost the same raw materials, assuming that there is no serious defects in the product, then the fan life is mainly determined by the life of bearings (ball bearings) . In addition to the effect of ball bearings on life span, the PQ / W test is the most important indicator of the performance of common products within the product life span. The efficiency of a DC fan can be represented by the following curve, the wind volume (Q) , wind pressure (P) the greater. The more air flow is provided to the system, the better the cooling effect is achieved. How can this be achieved? 

To understand the performance of a DC fan, you have to multiply P by Q and divide by the power consumed by the DC fan. Obviously, if the power consumed is lower, the fan can provide higher PQ, then the DC fan is even more powerful. If we draw two intersecting lines perpendicular to each other from the maximum points of P and q in the graph above, we can easily derive the area of the shaded part of the graph as (Pxq) / 2, the efficiency criterion (Pxq) / W is defined as the shadow area divided by the power consumed. Of course, one might argue that for a DC fan, the maximum point power consumed in q is less than the maximum point consumed in Q, in fact, the two biggest point is only used for comparison, there is no practical use value, and must be clear. For blowers, the maximum power consumption of the blowers at P is less than that at Q. The above is how to select good performance DC fan, we can be customized according to customer special requirements, if you want to know more DC fan knowledge can click: http://www.dxymotors.com