Archive for July 6th, 2009

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Compact fluorescent lifetimes

July 6, 2009

I CHOOSE to use CFLs.  I have strong objections to the federal government DICTATING that these lights be used.  My guess is the CFLs would totally sweep the light bulb market on their own if the lifetime issue, and other nuisance issues were resolved.  But when we are forced to buy CLFs there will little motivation for the CFL manufacturers to resolve these problems.

I started buying compact fluorescent light bulbs in the 1990s, and filled almost every possible light fixture in my house with CFLs.  I had been lecturing my children about the difficult times to come in their adulthood due to lack of energy.  I figured I was making a significant difference by reducing my electricity usage by tens or even hundreds of kilowatt-hours per month.

My goal was to save energy, but I expected that I would also save money.  Although CFLs have a high up front cost, they should pay for themselves in the long run by reducing the electric bill.  I made frequent visits to the hardware store, and always stopped on the lighting aisle to see what new configurations of CFLs were available.

I ignored some nuisances about CFLs in order to serve the greater good.  I noticed, for example, that a 15 Watt CFL that was supposed to replace 65 Watt incandescent was simply not as bright as the 65 Watter.   I noticed that they took a long time to warm up and reach their maximum brightness, and that this warm-up period seemed to get longer as the bulbs aged.  I told myself that I needed to adjust my lighting expectations and habits.  Within less than a year of my first CFL purchase some of the expensive bulbs started dying off.

When I sold that house in 2001, I left a fortune in CFLs in the light fixtures.  I thought I would leave behind a more energy efficient house to help the new owners get a head start on energy efficient living.  Then I spent another fortune equipping my new house with CFLs.  I have managed to keep my electricity usage to about 400 kilowatt-hours per month for a house that shelters 4 people year round (5 in the summer and during college breaks) by consistently replacing failing CFLs.  Otherwise our electricity usage would be about 550 kilowatt-hours per month.

However, I am getting annoyed with dying CFLs.  So about a year ago I started writing the installation dates on the base of each bulb whenever I replaced an old one.  I wanted data, not just memory, to tell me how long the bulbs last. 

Today I replaced my first dated CFL.  It was  installed in a recessed ceiling fixture in my basement on August 12th, 2008,  less than 11 months ago.  It failed in mid-June.  The first picture below shows my hand-written installation date on the base of the bulb.  The second picture shows the “retail product number” (BPCE15R30H/4) which I used to determine the manufacturer.  Oddly, although a brand name (Conserv-Energy) was on the bulb, the manufacturer (Feit) name was not.  I used the retail product number and looked it up at the EnergyStar websiteIMG_2445IMG_2451

According to the EnergyStar website the lifetime of this CFL was rated at 8000 hours.  It is a 15 Watt bulb designed to replace a 65 Watt incandescent.  We used it for, at most, 8 hours a day for about 10 months, or about 2000 hours.  This CFL saved on the order of 100 kilowatt-hours.  I pay about 10 cents per kilowatt hour when all the taxes and fees are added up.  So, the CFL saved about $10 on my electric bill over its 10 month lifetime, which was  enough to pay for itself with a few dollars to spare.  But it came nowhere near the manufacturer’s claim of saving $48 over its lifetime.

By the way, what fraction of United States energy consumption would be saved if 2/3 of all residential lighting were converted to CFLs?  See question 8 in this quiz to find out.

I will continue to monitor  the failure rate of the many CFL’s in my house.  Based on the first data point, this CFL was a useful investment if you can tolerate the nuisance factors mentioned above.

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