After plugging in one of the nightlights into a lit room, it instantly came on. I did not expect it to light up since the room I plugged it into was lit. It seems you have to have direct light shining on the nightlight for it to turn off - it would be nice to be able to adjust the sensitivity of the light sensor.The bigger issue is that after the first night of use one of lights stopped working. After unplugging and plugging the nightlight back in, it flickered on for a split second and stayed off (in a dark area).With that being said, the light they give off is bright but muted and would have worked well in our hallway had one not stopped working. I did not see much difference between the high and low light setting...it would be a little too bright for a bedroom even on low. Shipping back to Amazon (not being charged for shipping, and UPS picks up where they delivered it).