We just recently moved into our new house and had a similar issue. We thought it was one of the detectors chirping but what it was was our phone that was plugged into the receptacle under the bed that had both of our bedside lights and our phone plugged into the outlet that was attached to the switch that turned on our bedroom lights. Everytime that we turned on the lights something chirped. It was the phone starting to recharge itself..again.
I called warrenty and they plugged it in correctly.
I know.