Sun MIGHT help a new bin get started but after that They are pretty much self heating. I don't lnow your climate but here in the mid south we have to leep it moist in the summer [hot dry]season} but if too wet it will start to stink. Frankly I took my longest hose and used that as an arc [I didn't want to be able to smell it] did the same from the garden spot and the chicken house and placed my bins where the three arcs crossed one did end up under a tree and frankly I couldn't tell and difference between the bins. but my chickens liked to hang out on the shaded one {maybe for Hawk protection] ~gdShould compost bins have a certain amount of sun?? Would it be OK to have one in a shaded area. I am in NH and growing season is pretty short so I'd like to try to get really good soil.