It is important to note that main effects are calculated over all combinations of design variables in the DoE set. This is powerful because one can apply the information within it to a wide variety of designs. There may be individual cases where a design condition will not affect performance in the predicted way; however, the information contained in the knowledge-base should be considered similarly to heuristics: while not perfectly accurate in all cases, such tools are useful because they are reliable for most situations and are quick to use. Another feature of the knowledge-base is that it was designed to be customizable to specific design situations. There are a total of 1519 different permutations possible for specific combinations of season(s), time period(s) of day, and zone(s).