Shedding Light on LED's

From the "Thinking Green," column in the Duxbury Clipper by Dick Rothschild
Published June, 2015

Here we go again.  Just as you resign yourself to replacing the last of those dear old incandescent light bulbs with energy saving CFLs (compact fluorescents) you are being asked to jump ship again — this time for more efficient, longer lasting LEDs (light emitting diodes).  Be brave. Hold your nose and take the plunge. You will be lowering fossil fuel use, cutting climate changing CO2 emissions and shrinking your electric bill, all at the same time. And, you will be in good company. 

     Our local Stop & Shop in Kingston has just changed all their own fluorescent lighting to LED. To get the lowdown I met Mark Macomber at the store. Mark is the Energy Project Manager for Stop & Shop’s parent company, Ahold USA. 
     All 572 fixtures in the sales area of the Kingston store have been replaced. The change to LEDs, Macomber estimates, will slash their electricity consumption by a whopping 625,000 KwH (kilowatt hours) yearly. That’s saving as much electricity as turning off the lights in 367 houses in Duxbury for an entire year. If you prefer to think, instead, in terms of climate change impact, the changeover will reduce CO² emissions by over a million pounds a year, assuming the electricity is generated by fossil fuel.  As you might suspect, there is a financial motive as well behind this change, an anticipated yearly operating cost saving of close to $100,000 plus a bulb replacement saving of another $5,000. To maximize the efficiency of the new LED lighting system, it has been equipped with wireless controls making it easy to dim lights whenever conditions permit. The Kingston store is not alone. Ahold has partially or completely retrofitted 100 of its stores in 11 states with LEDs and has adopted other energy saving techniques such as equipping rooftop air conditioning units and condensers with variable speed drives and installing solar collectors at 38 of its locations. Combined, they insure that the supermarket chain will achieve its 2008 goal of reducing its carbon footprint by 20% by the end of 2015. 
      Enough about supermarkets. Let’s turn to something about LEDs nearer and dearer to your pocketbook, namely, “How much can I save by switching to LED bulbs?”  Because I can’t count the number of light bulbs in each of your households, I’m going to have to work with averages. Yes, yes, I know you are above average, otherwise you wouldn’t be reading this column.  
     Until recently, the average American household had 47 incandescent light bulbs, ranging from 25 watts to 100 watts. To simplify, let’s say they averaged 60 watts each.  That’s a total of 2820 watts (2.82kW) per household. If you were to replace those incandescent bulbs with 9.5 watt LEDs (which deliver equivalent brightness) you could reduce that 2820 watts to 446.5 watts.  At present the cost of electricity from NSTAR is 15.04 ¢ per kWh (kilowatt hour). Assuming that you use your lights about 150 hours a month (5 hours a day x 30 days), your monthly electricity cost for lighting with incandescent bulbs comes to $63.62 (2.82 kW x $0.1504 x 150 hours). By converting entirely to LEDs it is possible to reduce that monthly lighting cost to $10.06
     Now before you rush out to Lowes or Home Depot or your local electrical supply house or hardware store for LEDs, only to suffer sticker shock, let me elucidate. LEDs are costly compared to incandescent or compact fluorescent bulbs. A 9.5 watt LED replacement for that 60 watt incandescent is going to cost about $6 each, if you buy in 6-8 packs. That’s a premium of about $4 per bulb over the cost of an incandescent or compact fluorescent. But when you calculate the LED’s yearly cost, including electricity savings and bulb replacement savings, a different picture emerges. By the time your 60 watt equivalent LED celebrates its fourth birthday it will have saved you enough on your electric bill to have paid you back the premium you paid for it plus an additional $9 in replacement bulb savings. Over the next 10 years of its estimated life it will save you another $11 in electricity plus an estimated $ 22 in bulb replacements. Your total payback?  $46. Not bad for a $6 investment - especially when you consider that you’ll also be slowing down climate change and cleaning up the air we breathe.