Frugal lighting

Good Job.

Nick, this is much more useful than a lot of your pie in the sky calculations. Well done.

BTW, if the CFs were in a pack of four, did you test for variations? That would be useful information as well.

Also, did you check the lumen output either by using a standard candle, or a photometer (perhaps one in a camera?). Incandescent lamps dim with age, so using an older 100 watt lamp might have affected the results.

He might have been inept but his name has lasted longer than many who were ept :-)

How many of his critics' inventions are still used?

Mary

Many Thanks!

How did you measure 42.4cm from the bulb, or is that like R 3 aluminum foil..........

I lined up the center of each bulb on the 0 and 80 cm marks on a Craftsman 939675 8m/26' measuring tape, then moved the paper along the tape until the grease spot disappeared at 42.4 cm.

Nick

This part may not have been vital - but it's the sort of thing I love to know :-)

I'm sure many of his calculations are useful to people who want to be frugal - but I'm stunned that Nick managed this without a line of Basic code :-)

The numbers are interesting - the 23W CF really was approximately 23W but the 42W CF was much less. I'm not at all surprised that the 23W bulbs really aren't 100W-equivalent - typical marketing hype - but those results are acceptable to me.

Don't CFs dim with age? Can we then expect the relative efficiency to improve over time?

In Derek Broughton writes: [ various snippages ]

- also, keep in mind that the lumen ratings for traditional fluorescents are the initial output, but... it's _after_ 100 hours of burn in.

When first lit, they tend to be a modest amount brighter than spec. There's a rapid 'burn off" (for want of a better description, and then, at a nominal 100 hrs, they stabilize (to a slight long term downward slope).

So if you used brand new CFLs, you're seeing a bit of an artificial peaking...

Surprising...

No. I'm not sure how standard standard candles are. I've used CSA standard fingers...

I believe they do.

I doubt that. Don Klipstein might help here.

Nick

I think they dim cause the mercury sticks somewhere or soemthing, but no current drop I would think

//

Tut writes:

Nick, if you replace one of the lamps with a burning candle, you can calculate the strength of the each lamp in candles vs lamp wattage.

E=C/d^2--------> C1/d1^2=C2/d2^2

where: E=foot-candles C1= one candle C2= candles of light source d1= distance to oil drop for burning candle d2= distance to oil drop of lamp under test

I almost read that as meaning "the grease spot" that was left on the floor where Robert Bunsen was standing at the moment of the lab explosion.

Yeah, I've got some of those 100W equivalent, $8.97 bulbs, with a 9-year guarantee too.

I don't need a grease-spot photometer to tell me they don't put out as much light as a 100W bulb. My own eyes can tell me that. It takes a

The one in the hallway went out after about a year and a half to two years. I don't know where my receipt is, so I guess I'm out a few bucks.

These CFL's sure are frugal. Just make sure you send in any rebates and keep track of your receipts and the packing material for the next 9 years.

Don

It worked out to 79%, but still an energy bargain.

Maybe not. These bulbs have a phone number (800) 378-6998 and a date code V# xxxxx printed on the base. I called the number and gave them the code and they sent me a new one, after one died.

Nick

I think that too.

We pencil the installed date and the supplier on the item itself. We've only twice had to return them and they've been replaced with no receipt and no question.

Customer goodwill is important to stores. The items are cheap and it's recognised that some will fail.

Mary

No, not typically. Very few Gas Discharge lights dim with age unless the excitation voltage drops significantly. The Gas doesn't wear out, but the electronics that fire the voltage may.....

No, again not typically. Very few electronic systems get better as the components age, so efficency should slowly drop a bit with age....

IIRC, most do.

Nick

In my experience they do.

Mary