I bought 28 candles even though I have only 12 windows. With the flat bottom on the candles, they are able to stand on any flat surface which makes them perfect for emergency lighting instead of using open flame. I just turn them on and line them up outside a couple of days before an expected storm to make sure they are charged, shut them off at the end of the day and put them around the house the day of the storm so they are ready to turn on if the power goes out. Highly recommended!!