Ventilation fans, solar?

[Bradfo69]

Hi all,

Pics of the new greenhouse will be up soon but I've got a question regarding something I'm investigating. It came with a 16" Dayton vent fan and a powered shutter at the other end. Don't know cfm for the fan but I'll guess and say about 1,000. In Home Depot I noticed a 16" gable mounted solar powered attic fan that moves 500 cfm for about $180. My greenhouse is probably about 720 cf. I know you want to exchange the air about 1x per minute but, for the major savings in electricity, do you think this is worth considering? I'm looking to make this as cheap to operate as possible but, obviously want for it to be good for the plants. Thoughts are appreciated!!