Chris...

You've discovered why eagle eyes are so cheap. They DO rely on a temperature differential to "see" motion. If you are 90+ degrees and so is the outdoors, you'll be invisible to the eagle eye.

I had one looking out my back deck. In the winter it would signal if a bird flew by. On a 90+ degree day there can be a party on the deck and it won't go off.

My suggestion? Keep it, and just use it indoors. I doubt it's worth the money it'll cost to ship back to X10.

Dave