India, Nov. 21 -- Fairy lights create a beautiful atmosphere, but if you buy the wrong ones, they can guzzle power, break after a few years and even carry toxic chemicals. Here's what to consider when buying a set. Berlin (dpa) - Fairy lights are everywhere in the run-up to Christmas, but not all sets are equal. From colour temperature to IP ratings and safety seals, here is how to pick lights that look great, last long and do not waste energy. Seven tips for buying string lights: Check the colour temperature:Some fairy lights emit a warm yellow light, while others are a colder, bluish white. You can determine this by looking at the Kelvin (K) value on the packaging. Lamps rated at 3,000 K or less will give a warm, yellowish white light and...