Lightbulb wattage that is.  Use the lowest wattage bulb that will get the job done in your light fixtures.  This isn’t too important in fixtures that aren’t used much.  However, in light fixtures that are used often, the energy usage can far outweigh the additional light produced.

For example, we have a light fixture in our kitchen dining area that is turned on for 4 -6 hours per day.  Before we installed CFL’s in this fixture, we used 60 watt bulbs.  As they burned out, I just installed whatever I happened to have around in the in garage.  Before long, I noticed that 3 of the 5 bulbs in this fixture were 100 watts.  Not only did five bulbs at 60 - 100 watts each generate a lot of heat, but the light created didn’t really match our needs.  

Not a big deal you say?  Let’s do the math.  I was wasting 40 watts on each bulb.  Three of these bulbs used 6 hours per day for 365 days per year comes to 263 kilowatt hours (3 bulbs x 40 watts x 365 days divided by 1,000).  I’m currently paying $0.08 - $0.09 per kilowatt hour.  That comes to around $24 per year or $2 per month I’m wasting in just one light fixture.  

I agree, that number doesn’t scream at me — $2 per month after all is pretty small.  But multiply that times several light fixtures and it at least warrants a little attention.

Photo credit:  greekgod