LED Christmas Light Bulbs

C7 and C9 refer to the size of the socket on the Christmas light strings and spools. C7 Christmas lights have a candelabra E12 base and the larger C9 Christmas lights have an intermediate E17 base. When looking for replacement bulbs, know which size string you have. If you're not sure, measure the diameter of the socket or the old bulb's base. The number after the E is the diameter of the base in millimeters, so a C7 socket opening and a C7 bulb base both measure 12mm. The same is true for the C9s, but with a 17mm measurement.

C9 bulbs are also brighter and use more electricity per bulb. For incandescent bulbs, there's an approximate 2 watt difference, with C7s using about 5 watts and C9s using about 7 watts. This difference multiplied across a large display can really add up. Be mindful when connecting multiple strings so as not to exceed the maximum rating and burn out bulbs. That's a notable benefit to using LED Christmas lights. Both C7 and C9 bulbs use less than 1 watt, drastically increasing the number of bulbs that can be used on a single run.

When touring your neighborhood at the holidays, you may notice all white lights are not created equal. Some houses pop with bright white lights while others cast a softer glow, not quite as warm as incandescent Christmas lights, but close. The brighter crisp white light is from cool white bulbs and the warmer light is from warm white bulbs. Warm white deluxe bulbs are even warmer and are ideal for mantle decorating, along bannisters and stair railings, indoor wreaths, and other areas where a cozy firelight atmosphere is desired.