Measure light in lumens
Home lighting is changing. Incandescent bulbs are being replaced by CFL (compact florescent) bulbs and LEDs. According to a press release from the American Lighting Association, Starting January 1 2012, lighting products must carry labels that state light output in lumens, the unit of luminous flux, which is derived from the candela, the basic unit of luminous intensity.
Unfortunately, we’re used to buying light bulbs based on watts, the amount of power a bulb consumes. The watt really has nothing to do with light intensity, yet after over 100 years of using watts, we won’t change easily. How many years will it take for use to get used to buying lighting based on the lumens?
Having recently had to buy lighting for an entire house, I’ve tried to use CFLs in place of incandescent bulbs wherever possible, even replacing the incandescent bulbs that the electrician installed. There’s one place where I certainly wanted a CFL. It’s high above a staircase (see photo). I’m not going up there to change the bulb, ever.
CFLs do have some drawbacks. For example, a bathroom fixture has sockets for four bulbs. But, using four “60 W” CFL’s didn’t produce enough light. I tried to replace them with “100 W” CFLs, but with CFLs, more light means a larger bulb. The “100 W” CFLs were longer and wider than the “60 W” versions and opening the medicine cabinet door would have resulted in a broken bulb-not something you want considering the CFL bulb contains mercury. The compromise: use a “75 W” CFL.
Have you noticed that I’ve described the bulbs using watts relative to incandescent bulbs, not lumens? I’ll soon start using lumens, but I’ll have to translate that into watts relative to the old incandescent bulbs when speaking to others because most people will resist the change and will just be confused by the new units.
NPL, the UK national lab, has a page devoted to lighting units. You can find it here.
Martin Rowe commented:
The fixture in the photo was there when we bought the house. We had planned to replace it, but couldnt decide on a fixture by the time the electrical inspection rolled around so we just put back the old one. It had an incandescent bulb and I don't know how the previous owner replaced it. I figure that the CFL will last long enough until we replace the entire fixture.
WC commented:
I hope you have a good ladder. I have tried to be a good citizen, but CFLs just don't live up the the lifetime claims, even in those friendly "base down" applications. I suspect that, if everyone returned failed CFLs under warranty, we'd drive them out very quickly.
BobL commented:
For the CFL in the stairway fixture, I hope you bought a "good" one. One that will last with the base mounted up. One that will handle the heat.
As far as the bathroom fixture, why didn't four "60W" CFL's give the same light as 4 incandescents? A bathroom is one place where your wife would insist upon proper color temperature. I would have stuck with the incandescents.
You may have noticed, but I'm not a real fan of the CFL's.
