Is it Time to Buy LEDs?

cree-bulbQuite often I’ll get in to debates with friends and family about energy and we end up in conversations about why we choose to be a three Prius family and why I’m so hot on the Internet of Things and my investment in SmartThings‘ technologies. Where it gets tough, however, is justifying why we are replacing our incandescent light bulbs (and even compact fluorescents (CFLs)) with LED light bulbs since the costs of LEDs are still a bit high.

That LED bulb cost makes the return on investment (ROI) a little tougher to justify for purely economic reasons, except when you consider that one LED will last for ~25,000 hours and an incandescent for only 750-2,000 hours.

LED costs are coming down but, like my friend Eric said to me just last Friday, trying to time the purchase of doing a wholesale incandescent lightbulb replacement in your home is like “catching a falling knife.” Buy too early and you get hurt since the break-even will take too many years, though I’ll argue that the time is now to begin replacing incandescents (and CFLs) with LED bulbs.

For my wife and I it’s not just about cost, however. We strive to do our bit to minimize our energy footprint and try to positively impact human’s effect on the climate in a myriad of ways such as recycling more than anyone in our neighborhood. Our lightbulb replacement adventure is just starting but will add to our objectives of minimization. Every little bit helps.

So let’s take a look two examples of bulb replacement in my own home to give you a sense of what I’ve already done and what the results have been so far. Hopefully this will help you determine whether or not the time is right for you to “catch the knife” and replace your incandescent bulbs with LEDs.


The first thing we replaced were bulbs used in five lamps which burn for hours every day. I have them set to come on automatically in the house (using my SmartThings app and smart light switches, plugs and other ‘things’). These lamps burn for 7 hours per day in the winter months (~120 days of winter or 4,200 hours of use) and then for four hours per day the rest of the year (~245 days or 4,900 hours) which equals 9,100 hours used yearly.

LAMPHere is how our usage for those five lamps breaks down and the cost savings:


  • Number of bulbs: 5 incandescent 40W bulbs (use 40W each)
  • Yearly watts consumed: 9,100 hours x 40 watts consumed or 364,000 (364 kWh)
  • Cost* = $25 per year


  • Number of bulbs: 5 LED ‘equivalent 40W’ bulbs (use 9.5W each)
  • Yearly watts consumed: 9,100 hours x 9.5 watts consumed or 86,450 (86kWh)
  • Cost* = $6 per year


  • 5 LED 40 watt bulbs (we used the “warm white” ones by Cree  purchased at Home Depot for $9.97 apiece). Cost was $50.

Break-even is 2.5 years



  • Number of bulbs: 16 incandescent 40W bulbs (use 40W each)
  • Total watts consumed: 640 watts
  • Daily ‘Lights On’ Use: 2.5 hours or 1600 total watts
  • Yearly wattage used: 584,000 watts consumed or 584kWh
  • Cost* = $40 per year


  • Number of bulbs: 16 LED ‘equivalent 40W’ (or ’40We’) bulbs (use 9.5W each)
  • Total watts consumed: 76 watts
  • Daily ‘Lights On’ Use: 2.5 hours or 190 total watts
  • Yearly wattage used: 69,350 watts consumed or 69kWh
  • Cost* = $4.75 per year


  • One bathroom used 8 incandescent “dome” bulbs and the LED dome-type bulb replacement cost was $63.
  • Second bathroom used 8 LED 40 watt bulbs (we used the “warm white” ones by Cree purchased at Home Depot for $9.97 apiece). Cost was $85.
  • Total replacement cost was $148

Break-even is 4.2 years

*Current Xcel Energy rate averages (between summer/winter rates, residential with underground line service) $.06864 per KWH (kilowatt or thousands of watts used per hour) though that rate will rise in January 2014 by approximately 4%. Here is a breakdown of current Xcel Energy Rates (PDF).


600-01037305I’ve been asked, “What if you replaced them with compact fluorescents (CFLs)? Wouldn’t the ROI be quicker?

    • No for the lamps. Though CFLs cost less, surprisingly they burn 40% more wattage than LEDs (typically 13.5W for a CFL 40 vs. 9.5W for an LED 40We) and those five lamps are on for so many hours every day that the difference in energy use adds up fast.
    • No in one bathroom with “dome-type” lights but yes in the other.
      • Bathroom with “dome” bulbs: Surprisingly the cost for both bulbs and energy would have been higher. “EcoSmart” brand CFLs at Home Depot are $8.97 for a two-pack (great price for a “dome-type” bulb, by the way) or $72 vs. the $63 we paid at Costco for the LED dome bulbs. Plus the CFLs burn more wattage
      • Bathroom with regular bulbs: EcoSmart, 40W equivalent (uses 9W) aren’t comparable in quality to the Cree bulbs so this isn’t a fair comparison (the much more expensive Sylvania or GE bulbs are closer in quality to Cree) but the Philips are priced aggressively at $5.74 apiece for a “soft white” bulb that looks similar to an incandescent and outputs an equivalent amount of lumens. 8 of these bulbs would run $46 vs. the $85 we spent on Cree 40We bulbs.


Here are a few thoughts and next steps for us:

  • It surprised me that the bathroom’s break-even wasn’t faster since the incandescents we had in there burned so many watts. The bathroom light bars just aren’t turned on long enough each day to make a huge difference in energy cost
  • The light from the Cree, warm white bulbs is incredibly pleasing. I often test people when they come over to the house to tell me which is an incandescent and which is an LED. 90% can’t tell the difference
  • I had to ask Cree for recommendations on dimmers (PDF) with LEDs. After installing the Cree LEDs in our master bathroom it was SO much brighter that I headed to Home Depot, bought a Lutron dimmer for $20, installed it but couldn’t get rid of the radio frequency interference (RFI) “buzz” from the bulbs. Although most dimmers contain a filter to suppress RFI (and I thought that a $20 dimmer would be good but it wasn’t) additional filtering may be required. I’ll pick one or two from Cree’s list and try them, but keep this in mind as you install dimmers.
    • (Note: We have dimmers in several rooms with Cree 40We bulbs in their ceiling fixtures and have zero problem. The Lutron dimmer can handle a 600W load so, with only 76W being pulled by the 8 Cree bulbs installed, that shouldn’t be an issue).
  • We are not buying CFLs anymore. They require special handling due to the mercury (and it is a real mess if you break one), they cost more and use more energy, and you can’t just toss them out (you have to take them to an approved drop-off location).



Here is a useful chart from that will give you, at a glance, some information about lighting types, their lifetime and their performance:


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  1. Alan Geeves on November 19, 2013 at 6:25 pm

    Best way to replace bulbs of any type is when they fail. I started doing this 10 years ago with cfl bulbs and one light that doesn’t get used much still has its original incandescent bulb in it. I have started down the led way 6 months ago but it could be 2 years or more before every bulb is replaced. In New Zealand LED bulbs are still 5 times the cost of a CFL but that will change.
    I dont care if a light fitting with multiple bulbs has mismatched bulbs but others might so where I can replace 1 bulb others may be compelled to replace the set. If thats the case those bulbs can still be used in other fittings

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Podcasting hit the mainstream in July of 2005 when Apple added podcast show support within iTunes. I'd seen this coming so started podcasting in May of 2005 and kept going until August of 2007. Unfortunately was never 'discovered' by national broadcasters, but made a delightfully large number of connections with people all over the world because of these shows. Click here to view the archive of my podcast posts.