see. the power of devices are given keeping in mind their parallel connection,since all the household connection are in parallel.Now for parallel connection for power v use the formula

this is because in parallel connection V is same.

so for higher power , the resistance of the device is kept low.

 now if v use this device in parallel the constant parameter will be current not voltage. therefore for calculating power we will use the formula

now since the resistance is low, the power is less.

Now,  i think u can understand the concept behind this.

plz... rate if i m clear and u got ur answer. enquire further if still there is some doubt.