Low Watt Bulbs: A Bright Idea

by Dave on June 5, 2009

As first published in Coastal Sussex Weekly, May 7, 2009:

by Matthew Peterson

Most of us have seen, used or at least heard of Compact Fluorescent Lamps (CFL for short) over the last couple of years.  They are all the rage in reducing electricity costs without having to tear something out and put something new in – all you have to do is replace one bulb for another, albeit more expensive, light bulb.  While there are the positives of longer life span, less electricity cost, and more efficient lighting, there are some common negative thoughts – upfront cost over what will “really” be saved, light ambiance similar to that of a gas station bathroom, and mercury, oh, the mercury.  Let’s dispel some myths and get some answers.

How much more efficient are these bulbs over the standard incandescent?  Quite.  Incandescent bulbs produce heat and light – both of which cause energy to be used and since we can’t see heat, that electricity is wasted.  Incandescent bulbs produce around 15 lumens per watt of input power and CFLs can produce between 50 and 100 lumens per watt.  That would mean that CFLs are four to six times more efficient.  That is the reason behind buying a 15-watt fluorescent bulb to replace a 60-watt incandescent and both produce the same amount of light.

Lifespan in the world of bulbs is measured in hours.  An incandescent bulb is generally rated for 1000 hours of use.  A CFL is rated at a minimum of around 6000 hours – six times longer than that of a typical bulb.  While the purchase price of a CFL is typically three times greater than that of an equivalent incandescent lamp, the extended life and reduced energy use will more than compensate for the increase in cost. One study reported that if every incandescent bulb in a typical American household was replaced with a CFL, a 12% discount on utility bills could be realized.

Ok, time to talk some mercury.  There is a friend of mine, who shall remain nameless, that uses mercury vapor as his reason for not adopting the use of CFLs.  The Environmental Protection Agency estimated that if all 270 million compact fluorescent bulbs sold in 2007 were sent to landfill sites, that this would represent around 0.13 tons, or 0.1% of all U.S. emissions of mercury (around 104 tons) that year.  So while present, that amount of mercury being put into landfills is somewhat negligible.  Another study that I read the results of – and this is probably stretching it even for an environmental conservationist like me – is that if power is being produced by a coal burning power plant, the reduction in energy demands by using a CFL saves on mercury being released into the environment because coal burning plants give off mercury vapor as a by-product.  I know, I know….Also noteworthy is that the Delaware Solid Waste Authority has collection events (quarterly for each county) for Household Hazardous Wastes, which CFLs and other fluorescent bulbs are considered and this is the proper way to dispose of these products.

The most important idea in lighting design is aesthetics.  Light can make a home warm or cold, light can make a person feel safe or confused, and light can make or break a home design.  This has, quite honestly, been the biggest reservation in my switching over to CFLs.  I have used them in lamps with shades, in closets, in utility rooms, but have hesitated in main living areas because of the ‘operating room’ effect of certain colors.  Because CFLs radiate a different light spectrum from that of incandescent lamps, the colors given can seem quite “blue” or “white” as compared to the “orange yellow” glow of an incandescent.  The good news is that most manufacturers recognize this as a barrier and have worked on improving the light quality.  Light quality is measured by the degree of Kelvin that is produced.  Incandescent quality lighting is around 2400° K – the typical CFL is in the 4700-5100° K range. There are several brands and wattages available now in the parameters to which we are accustomed that bring the light quality into the 2600-2750° K range.

If you decide to “make the switch” remember that in determining what wattage you need in a CFL, take the wattage of the incandescent that you are replacing and divide it by four.  One more suggestion as we try to reduce utility bills and help save greenhouse gases– and I know that you have NEVER heard this from the age of 4 through 18 – is to turn off the lights when you leave a room.  I am a conservationist that believes every small gesture can positively impact our environment – so think about when lights need to be on, when you can take advantage of daylighting, and think about using as little electricity as possible.  All right, better get off my soapbox and get back to work.

Matthew Peterson is the Principal of Element Design Group in Lewes. He can be reached at matthew@elementdg.com.

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