Outside Light Bulbs And Cold Temps

Many parts of the United States are experiencing some serious cold winter weather this season and I received a few emails asking about outside lights. Many Going True Green readers and members have compact fluorescent bulbs in outside fixtures. Depending on where we live, most compact fluorescent bulbs have not caused any issues until this season's long cold snap and a bomb cyclone winter storm that hit the Northeast. 

Below are some of the questions and my answers:

​- How come my outdoor Compact Fluorescent Bulbs are so dim over my front door?
– Why are my fluorescent light bulbs outside only half as bright as normal?
– My energy saving fluorescent bulbs outside are hardly coming on since our 7 degree temperatures?
– Will LEDs do better in cold temperatures?
– Should I switch back to regular light bulbs for outside?

Most Compact Fluorescent bulbs have a lower lumen (light level) output below 32 degrees Fahrenheit. Then light levels drop off "Big Time" below 20 something degrees Fahrenheit as shown in the image.  Any temp lower than that, most of these bulbs don't even come on! They may just glow a little, but no significant light level is provided. Additionally, these lights will still cost us the full wattage of the bulb in electricity even though we are not receiving the proper light level. In other words, that outdoor 20 watt compact fluorescent bulb (able to give off a light level equal to 75 watts) is still costing 20 watts in electric power, but only giving off about 3 watts of light when outside temperatures are severely cold. Another negative factor is the bulb's life will be cut short as the components struggle repeatedly to work properly in temperatures dropping toward zero degrees.

​Don't even think about switching back to regular incandescent bulbs for outside. They too will burn out faster because of the heat they produce vs the cold outside air. Did you know that with the energy used by a regular light bulb, 90% produces heat and only 10% omits light? Also switching will just run up your electric bill, because now you will have a 75 watt bulb in place of the 20 watt compact fluorescent.

As for LED light bulbs, they will get brighter in colder temps! Additionally you will be only using a 14 watt LED (current technology, LEDs are getting more efficient) to give off 75 watts of light. So to make the long dark winter nights a little brighter, start to change over to new LED bulbs. We will all save a little more on the electric bill, some energy for tomorrow, and have a brighter front doorway.