It's under the eave of our 2 story house, even with the window in my home office so probably at least 16' off the ground. I assume higher is better to be free of predators? Our house faces south and this box is on the West facing side.
Our east facing side is completely smooth (no gables or windows) so plenty of room for a box over there and the wife asked me to build another box for her, probably this weekend.We have seven Screech-Owl nest boxes on our farm and usually get a winter roosting bird in one or more boxes. We have pretty good habitat but in 30+ years have only had two Screech-Owl nests, both successful. Competition from Great Horned and Long-eared Owls may be a factor as both will predate the small owls. We've had many more nests in the boxes by American Kestrels, almost every year. I doubt you will ever get a kestrel in that box location so flickers may be your best bird. Kestrels are very sensitive to human disturbance. Non-native Starlings and House Sparrows will be a problem. I always remove their nests once they lay eggs.
You might get lucky by putting up another box or two on the house or a nearby tree, facing east is best for Screech-Owls. Enjoy your winter roosting bird while you can.
Thanks for the tips!