OK, I just talked with an installer and he says that the efficiency number on the spec sheet of a bifacial includes the backside. So a smaller non-bifacial panel of the same efficiency may be better if it doesn’t have much space behind it and space is limited. Bifacials are actually lower in efficiency on the front side than the advertised number? It seems to me I heard that the wattage and efficiency numbers were published only from the front side. The backside was extra.
Anyone have a definitive answer?