The 1W PET panel that I sold on Taobao, without frame, measures 13*11=143 square centimeters.
I also have 5W 30*23=690 square centimeters, the average is 138.
There is also 180W, or 158*81/180=71 square centimeters.
Generally speaking, 70 square centimeters/W is already a relatively low value, and there are almost no values lower than this.
There is something wrong with your expression, I suggest you rearrange it.
D9=What is B9?
I saw your photo:
Column B is the zone number, column C currently only has a kitchen and a bathroom, and the column D has 2 options (with/without solar energy).
Do you mean: when solar energy is needed, E9=B9+5, and when solar energy is not needed: E9=B9?
If this is what I explained, this amounts to a condition of judgment. If D requires solar energy
The formula for E9 : =if(d9="Need solar energy",b9+5,b9)