You can buy the battery operated candles at Bed,Bath & Beyond, A.C. Moore's, Michael's, Plow & Hearth and they are wonderful. That is all we use anymore in our house. We live in a Sr. Citizens community and about 3 yrs. ago there was a bad fire in a garden apt. one windy Jan. night started by a plastic coffee maker being put on a burner that was on by mistake. A man lost his death because he went back into his first floor apt. to get some important papers and the ceiling from the apt. on fire fell on him and killed him. They had to tear the entire building down and rebuild it. Every since then, we only use the battery operated ones. They have some that are scented and the outside feels like real wax. They have a lot of hours of use, something like 100 or 500 before you have to replace the batteries. They are LED lights. Candles that come in lots of colors plus white and off white.

Posting this in case it helps someone with the same problem I had. I installed several sets of LED puck lights under my kitchen cabinets and they worked fine for about a month before they began to flicker and even fade. This happened independently (and not at the same time) to all 4 sets and had me puzzled for a while. These were sets purchased from Home Depot that had a switch (on the DC side of the transformer) and their own transformer which I had put into a junction box. I just left the switch on because I was using the wall switch to turn them on and off. It turns out that the switches that come with these lights are awful. When I opened up the junction boxes I discovered that when I held the switch hard in the on position the lights would be brighter and not flicker. So I merely cut out the switches and spliced the 12V wires together. Problem solved and a lot less stuff in the junction boxes!

Post this in the Electrical Forum, it's very active there. When the light gets brighter without flickering is there an electric dryer or electric stove/cooktop operating? For the nonoperating lights look for a GFCI in the garage or other unlikely place.

Are all of these lights on the same circuit (same circuit breaker or fuse)? If so, my guess would be that you have a loose connection somewhere in that circuit. Yes, it can be moderately dangerous because loose connections can heat up and cause fires. I'd certainly have this checked as soon as possible.