I haven't been able to find anything on google about this other than closed Windows which I know don't let UVB through. I have a window in my living room by the couch. So when the sun shines it it shines right on the couch where my Zeus likes to sit. Lately, it's been a little too hot for me to sit out with him (high 90's and no shade for me to sit. So on days like these I open that window and let him sit there. (I'm lucky with my apartment that even with the windows open on hot days it tends to stay pretty cool). So my question, if I let him sit in the window for extended periods of time, would he still be recieving a beneficial amount of UVB through the screen?