Friday, November 14, 2014

All incandescent bulbs must be destroyed

If you saw an investment opportunity where you were guaranteed 100% return per year, would you take it?  Incandescent bulbs (you know, the regular cheap kind) cost far more in electricity usage than the sticker price at the store. If you have them plugged in anywhere in your home, they are unnecessarily costing you more.  If the sticker price at the store included the cost for the electricity they will consume over their lifetimes, no one would buy them.

So now for the investment pitch: replace all lighting in your home with LED lighting, and throw away the incandescent bulbs so nobody plugs them in by accident.  The LED bulbs are at least 6 times more efficient, and will pay for themselves in savings in as little as 8 months.

(read in Jim Gaffigan  audience voice)  Throw away the incandescents? That's so wasteful!
 Nope. Plugging them in and having them waste energy ever again is way more wasteful. Send em to the landfill.

The bulbs will pay for themselves in savings - it's just a matter of time.  to calculate the savings from a bulb purchase, you will need to know:

  • C = Your electricity cost.  There is a standard rate on the bill, but don't forget to add in any taxes or per kwh fees. Mine works out to $0.14 after all taxes and fees.
  • H = How many hours per day the replaced bulb is used. for this example let;'s say 4 hours per day.
  • W = the old incandescent bulb wattage (usually 60)
  • N = the new wattage for the LED bulb (usually 9.5 for a 60W replacement)
The savings per month are (H*W - H*N)/1000 * C * 30 

So in our example, the monthly savings will be around $0.85 per month.  If I got the bulb for $5 (yes, $5, at Ikea), the payoff period will be under 6 months.  Every 6 months a little green leprechaun hands me $5.  And all I had to do was replace a light bulb.  Oh, and did I mention that these new bulbs will last 20 years?

Now that you are sold on this investment, you have the task of selecting the brand and type of bulb. Here are the standard ratings that differentiate what type of light the bulb you are getting:

  • Brightness: All bulbs are measured in lumens. A 60W bulb from the dark ages puts out around 800 lumens. Anything from 700 to 900 will look similar in brightness.
  • Color:  The color of the light (or yellowness) is measured as a temperature, corresponding to the blackbody radiation spectra of a material heated to that temperature measured in Kelvin, or K for short.  Soft white is the most common at 2700K.  Bright white will be some higher number.
  • Color Rendering Index: This is the accuracy of the bulbs attempt to replicate an incandescent bulb. A score of 100 would be perfect and no one could tell the difference. Some brands advertise this number, which is a good sign that they have done some engineering to get the bulb to put off good light.
  • Dimmable: If you have a dimmer switch, make sure it says "dimmable" without the "not" in front of it somewhere on the package.
  • Enclosed fixtures: If you are installing in a closed fixture, be sure that the packaging is marked as being rated for enclosed fixtures.  The reason some bulbs will not work in enclosed fixtures is due to the heat being dissipated from the bulb. Although this is much less heat than an incandescent, it is enough to damage the bulb if it builds up in the fixture.
Here are a few bulbs that I have purchased and tested, and have found to have acceptable light color and brightness:
  • IKEA - yes, IKEA has 700 lumen LED bulbs at $4.50.  Some have a transparent case and look nice in exposed fixtures.  They have a few different styles to choose from.  Good light color and are dimmable too.
  • Phillips - In my opinion the best brand for bulbs, but not cheap.  I have Phillips for all my overhead recessed lighting.  $12 to $20 each.  Home depot stores in minnesota have some bulbs at reduced prices, thanks to subsidies from XCEL energy.
  • Feit - $6 - $12 each - Costco had a deal on these last month.  Feit bulbs were among the best rated on consumer reports.
While typing this I have completely forgotten to mention the real reason I am typing this blog, which is the fact that with each incandescent bulb that gets replaced by something more efficient, the ice caps will melt at least a little less fast.  But even if you don't believe "science", there's no denying your wallet.  

1 comment:

  1. Thanks John, impressive work! I am an Xcel Energy employee and I manage the lighting programs. This is exactly the information that Xcel Energy is working to communicate to its customers. Ditch incandescent bulbs and switch to LEDs! LED bulbs will save you about 80% over incandescent bulbs. For the most up-to-date information on LED discounts offered through Xcel Energy, visit On this website you’ll find the retailer, model number and promotional price of the Xcel Energy discounted bulbs.

    If the energy savings alone doesn’t sell you on LEDs, you might want to consider that LEDs perform better than CFLs in most applications and are mercury-free. Also, contrary to CFLs, LEDs have shown no lumen degradation over time according to the DOE (Department of Energy). That means that after five years, your LED bulb will still be burning as bright as it was the day you purchased it.

    Another interesting tidbit about LED bulbs is that they have increased significantly in energy efficiency since they launched in the residential market in 2007. At that time, a 60 watt equivalent LED bulb (800 lumens) was 12.5 watts; today an 800 lumen LED bulb is about 9.5 watts, as you noted above. By the year 2024, an 800 lumen LED bulb is projected to be less than 5 watts! But don’t wait until then to buy one, between now and then you could pay for just one bulb ten times over in energy savings!

    Kim Sherman
    Product Portfolio Manager
    Xcel Energy