Detailed answer regarding Ceiling Fan Direction. During the summer, you want the air blowing directly on you so you will feel cooler from the wind chill effect (which is how fans cool you off). So stand under the fan and turn it up on high speed.
NRR STANDS FOR NOISE REDUCTION RATING. NRR (noise reduction rating) is a single number rating method which describes a hearing protection device (HPD) based on how much the overall noise level is reduced by the HPD. Most noise measurements in the industry are derived from the A-weighting scale.
For example, lets say your Signal value is -55dBm and your Noise value is -95dBm. -55dBm + -95dBm = 40db this means you have an SNR of 40, the general rule of thumb is that any SNR above 20 is good. Other important terminologies that we need to understand is the EIRP and Free Space Path Loss.