Today would be a good day to throw away those old compact fluorescent light bulbs — even if you are still using them.
This suggestion goes especially for those of us in the northern temperate latitudes where the heating season is now effectively over. The waste heat from low-efficiency lighting like compact fluorescents is not wasted while you are heating the building, but the cooling season is another matter entirely. In the worst case, if you are generating large amounts of waste heat, then removing it with air conditioning, the cost of the electricity to do this for one summer can exceed the value of the light bulb.
My house is about one degree cooler in summer since I replaced the old low-efficiency lighting with up-to-date light bulbs. It is an easy change to notice on a hot day, and it cost essentially nothing to do.
If your heating season is just getting started as you read this, consider taking this step at the end of the season when summer weather arrives.
Current light bulb technology is about twice as efficient, and it costs less than you probably paid for the now-obsolete compact fluorescent bulbs ten years ago. Another advantage is that they are thought to last 30–50 years, which for most of us means they will still be working when we move out. Imagine a world in which, when a light bulb burns out, people say, “Now, that’s strange.”
The change of season is reason enough, but there is another reason to throw away all of your compact fluorescent bulbs at once. In most places, compact fluorescent bulbs cannot be placed in the trash. That is because of the toxic chemicals they contain. To throw them away, you may have to take them somewhere, as guided by local government web pages. As long as you have to make a special trip, you may as well be done with it in one trip.