No not positive it's electrical at all, no light flickers and noises [that I'm aware of...I don't have tv, so it's pretty quiet]. It's very out of the blue, usually scares crap out of me and dogs. I just can't think of what else it would be. The only thing I can think of, is it did seem to happen more when it was really cold out...when we were getting below 0 or real low temps, it seemed to happen a little more. Not drastic, but enough to take notice it was more than just a one time occurrence.