Design parameters for a centrifugal blower includes, power of a motor, impeller diameter, impeller width, impeller rotational speed, volume flow rate and number of blades in an impeller, while relationship among several of this parameters are well defined in literature, it is unclear as to how the number of impellers blades affect the performance of a blower. In this work, an experimental method to determine the effect of number of blades in an impeller is described. The blower has been tested at three different speeds using five fabricated impellers with 4, 5, 6, 7 and 8 blades respectively. It is found that, for all 3 selected blower speeds, air flow rate increase by about 19% by increasing the number of impeller blades from 4 to 8. It is also found that increasing blower speed has a significant increase in flow rate; that is, more that 80% increase upon doubling the number of impeller blades. It is also found that there is slight variation in power consumption due to change in number of blades. It is therefore proposed that changing the number of impeller blades can only be applied to fine tune the blower design within 15-20% flow rate variation. However nominal flow rate has to be established using blower speed and dimensions. Power consumption if found to increase slightly with maximum variation of 3% on increasing blade number from 4 to 8. The results are useful in the design or re-design of fabricated blowers and selection of suitable speed. When space is a constraint, increase in the number of blades or blower speed can respectively be applied to increase air flow rate depending on the magnitude of the increase required.