I put three salvage Andersen casement windows in mine. They have screens, which keep out the flies/moths, and believe it or not, birds, who insist that the shack is the perfect place for their nests. I keep the upper windows open all season to help draft out the steam, and in the off season to keep the place aired out. This is particularly necessary while the pans are soaking in sour sap, which can smell disgusting.
My shack is really too small for any outer purpose in the off season, but it's attached to a bigger barn which holds everything else. I will just put all my supplies in there, and aside from the occasional maple tour, don't visit too often except when working on the building or equipment.
Gary / Zena Crossroads / 42˚ 00' 24" N / Hobby in Early '70s, Addiction since 2014
175+ taps on 3/16 (60 of which are on two Lunchbox Vac/Releasers)
12x34 timber framed sap house w/attached 10x34 shed roof for storage
2 x 6 Smoky Lake hybrid pan on Corsair arch with AUF/steam hood/preheater/concentric exhaust
7.0 KW Sun Power PV System, Smokey Lake Filter Press/Steam Bottler, Modified NGMP RO - 2 4x40 posts 200 gph