Donna, I guess I questioned this because my boxes are in full sun and it gets very hot inside those boxes in the summertime. I always use Styrofoam heat shield on nests (being sure not to cover my ventilation areas) if they are active in June and further out. Maybe up North there you don’t have the heat we have here in the Midwest in the summertime. But I really think a Gilwood needs that extra top ventilation is you were to use a wren guard, as I always do. But maybe it does still get quite a bit of air even with the guard on – I don’t know. P.S. my wren guard does have sides, but they do not cover up the existing ventilation slots on my boxes.