We recently moved into a new house and still are working with the contractors to work out a few issues. From what I can see, we have the same smoke detectors in each room/area. All have two lights. One red light flashes every 45 seconds or so, which I am told is correct. The other light is green. On some smoke detectors it is a sold green and on some it is a flashing green light. Can you tell me why some have a sold light and some are flashing? It's late at night and I don't want to wake the kids otherwise I'd check to see which ones have batteries and which ones don't. Could that be the reason for the flashing light?