CFL's only 12% more efficient than incandescent?

[klrman]

I heard the last part of this in the news a few days ago. Is it true that cfl's are only 12% more efficient than regular light bulbs? My brother heard it too.

 

[blasterman]

This has to do with several test confirming efficiency problems with certain CFL ballast types. I've seen this explained in detail on several web-sites. I'll try to find the links.

The lights themselves are tremendously more efficient than incan/halogen. Bi-pin CFL for instance, or standard fluorescent tubes using a good external ballast prove this out.

 

[blasterman]

Darn...can't find that link.

There's also the rather strange explanation that claims inefficient lights, such as incan, are as power efficient as LED or fluorescent because if you live in a northern climate the wasted energy (heat) simply displaces the need for gas heating. I haven't entirely wrapped my brain around that one.

 

[holiday light express]

Umm, most light bulbs are in the ceiling, so the heat just floats up, so you really won't gain much heating power. Plus you would have to find a way to evenly heat with light bulbs.. and at that point, you will have a really bright house, just to heat it... Not really that efficient.

 

[Benson]

There's also the rather strange explanation that claims inefficient lights, such as incan, are as power efficient as LED or fluorescent because if you live in a northern climate the wasted energy (heat) simply displaces the need for gas heating. I haven't entirely wrapped my brain around that one.

Yes and no; in most climates, heat in the summer is not needed or helpful, and electric heat may cost more than gas, so even if it's not "inefficient", it may still be expensive.

Also, if you use a heat pump, you can get "efficiency" (defined as heat added over energy consumed) greater than 1, as 1 watt of electricity can be used to transfer 2 watts of heat, rendering lightbulbs (or any resistance heaters) less efficient for heating.

However, if your roof is decently insulated, you use (resistive) electric heat, and you're actually using your heater year-round, it's true -- more power burned by lights is offset by less power in the heater, and the only benefit of high-efficiency light sources is the ability to toss more lumens out of the same fixture (at maximum rated power), which is rarely needed.

 

[jtr1962]

There's also the rather strange explanation that claims inefficient lights, such as incan, are as power efficient as LED or fluorescent because if you live in a northern climate the wasted energy (heat) simply displaces the need for gas heating. I haven't entirely wrapped my brain around that one.

There are very few places people live where heating is needed year round. In the continental US, the cooling season runs anywhere from perhaps 2 months in places like the north central states to 12 months in the south. Average is probably somewhere around 4. And the heating season probably averages about the same. Any savings in the colder months are generally offset by increased power usage in the warmer months. Not to mention that with today's well-insulated homes you might actually need to actively cool even if it's 30°F outside if you use enough incandescent lamps. Office buildings and stores have had this problem for years, even with the power savings of fluorescent lamps. Typically you need to either run the A/C or bring in cool air from outdoors until temps drop under 30° to 40° F.

And then there are other factors. Incandescents just don't last long compared to alternatives. Even if there was no efficiency difference at all I would still use flourescent just for the increased lifespan.

It also bears mentioning that part of the drive towards more efficient lighting has little to do with saving energy. If we wanted, we could build a bunch of new nuclear power plants. Problem is the grid couldn't deliver all that new power. It's already overtaxed, especially in the summer. Anything we can do to lessen the strain until the grid can be upgraded is a good thing. So is avoiding the need to build new power plants.

 

[ponygt65]

***awaiting links of CFL only being 12%***


sorry, I dont' buy it worth a crap.

 

[blasterman]

Umm, most light bulbs are in the ceiling,

Again, not everyone bought into recessed lighting during the housing bubble. My house was built in 1922, hardly has modern insulation, and yet my electric bill is a fraction what my friends spend with their 'modern' houses and inefficient rows of lighting jammed in the ceiling.

I have a 7yr old boiler, and even with a poorly insulated 1300 square foot attic/apartment on my second story my heat bill is on par with newer houses using forced air. The reason being I only run the boiler lines to areas of my house I spend time in - not try to heat every square inch of atmosphere in the space.

I'm hardly on the side of incans for any consideration and consider residential lighting needs in the grand scheme of things to be a waste of debate. Heating needs, cooling needs, and having living spaces larger than we can afford (but won't admit) are a 1000x more of a problem. Still, it's a practical fact that a couple incan bulbs in lamps in your living room next to where you sit will consume less power than filling rows of recessed lighting with CFL

 

[ponygt65]

I'm hardly on the side of incans for any consideration and consider residential lighting needs in the grand scheme of things to be a waste of debate. Heating needs, cooling needs, and having living spaces larger than we can afford (but won't admit) are a 1000x more of a problem. Still, it's a practical fact that a couple incan bulbs in lamps in your living room next to where you sit will consume less power than filling rows of recessed lighting with CFL

That has more to do with design than the recessed CFL's though.


ALOT of myths and 'made up minds' are based on poorly designed lighting setups. And it's sad. ALot of designers, architects, and even electrician's couldn't properly specify lighting. We get calls all the time for it. I see desingers and Architects at lightfair all the time that couldn't design a freakin' coat closet.

 

[asdalton]

There's also the rather strange explanation that claims inefficient lights, such as incan, are as power efficient as LED or fluorescent because if you live in a northern climate the wasted energy (heat) simply displaces the need for gas heating. I haven't entirely wrapped my brain around that one.

It's true, as long as 1) you are talking about the heating season (in the summer with AC it works against you), and 2) you are considering purely energy use and not cost (gas is not the same as electricity).

 

[ponygt65]

It's true, as long as 1) you are talking about the heating season (in the summer with AC it works against you), and 2) you are considering purely energy use and not cost (gas is not the same as electricity).

I'm willing to bet the review didn't consider the cost in change lamp a every 2k hours, versus lamp b every 10k hours.

 

[65535]

How did this get turned into a HVAC discussion?

Per unit of light CFL's have a far higher efficacy.

 

[LEDninja]

Careful reading of the article indicate the source is not making a direct comparison between CFL and incandescent bulbs. It is comparing the total electricity bill. (CFL light bulbs + refrigerator + stove + water heater + TV + computer +...) vs. (incandescent light bulbs + refrigerator + stove + water heater + TV + computer +...) Because lighting is only a small percentage of total electricity usage the savings are only 12%, not 75%.

From http://en.wikipedia.org/wiki/Compact_fluorescent_lamp#cite_note-20

Cost
While the purchase price of an integrated CFL is typically 3 to 10 times greater than that of an equivalent incandescent lamp, the extended lifetime and lower energy use will compensate for the higher initial cost.[20] A US article stated "A household that invested $90 in changing 30 fixtures to CFLs would save $440 to $1,500 over the five-year life of the bulbs, depending on your cost of electricity. Look at your utility bill and imagine a 12% discount to estimate the savings.

wikipedia linked to http://www.usnews.com/articles/busi...-the-end-of-the-light-bulb-as-we-know-it.html

How do I save money, when a CFL costs six times as much as an old-fashioned bulb?
Each cone-shaped spiral CFL costs about $3, compared with 50 cents for a standard bulb. But a CFL uses about 75 percent less energy and lasts five years instead of a few months. A household that invested $90 in changing 30 fixtures to CFLs would save $440 to $1,500 over the five-year life of the bulbs, depending on your cost of electricity. Look at your utility bill and imagine a 12 percent discount to estimate the savings.

 

[Illum]

Efficiency is not based simply on performance, but as a sum and a derivative of the total cost versus the marginal benefit that came from the product after production.

Building a regular incandescent lamp requires
Metal sleeve
argon gas
Tungsten metal
Vitrite insulation
Glass globe
Not too much stuff, and most of it can be recycled either by reusing, smelting, or absorption.

Now the CFL just the ballast alone is complicated.
plus the hazard like phosphor powder, mercury vapor...plus whatever non RoHS materials used in it...contributes to a HUGE cost to recycle them...heck, I haven't seen a bin around here that advocates recycling them. What I have seen is broken ones in dumpsters that looks like they were shot to sh1ts by a pellet gun.

I've seen too much in dumpster diving trips...
Whats seen...can't be unseen:shrug:

 

[R33E8]

Maybe they are comparing luminous efficiency vs luminous efficacy (lm/w)?

 

[ponygt65]

I think there is some confusion between usage and reduction. ~12% of energy usage in residential is contributed to lighting.

CFL's have a 75% reduction in energy by comparison of efficacy within the lighting itself. 12% of your bill is lighting. You will see a 75% drop of that 12% (roughly). So over all you will not see a 75% reduction in your bill. Also, that breakdown doesn't take into account the added cost of the 5-7 incandescents that you will need to purchase in the life time of the CFL.

There is alot to look at when doing energy Calcs.

 

[klrman]

Efficiency is not based simply on performance, but as a sum and a derivative of the total cost versus the marginal benefit that came from the product after production.

Building a regular incandescent lamp requires
Metal sleeve
argon gas
Tungsten metal
Vitrite insulation
Glass globe
Not too much stuff, and most of it can be recycled either by reusing, smelting, or absorption.

Now the CFL just the ballast alone is complicated.
plus the hazard like phosphor powder, mercury vapor...plus whatever non RoHS materials used in it...contributes to a HUGE cost to recycle them...heck, I haven't seen a bin around here that advocates recycling them. What I have seen is broken ones in dumpsters that looks like they were shot to sh1ts by a pellet gun.

I've seen too much in dumpster diving trips...
Whats seen...can't be unseen:shrug:

That's very interesting as a sum of the whole! It was just mentioned that a manufacturing plant in Europe was closed due to some deaths from the mercury that was used to make cfl's. If one looks at the whole cycle from manufacturing to the disposal, cfl's just don't seem to be that great of a deal.

 

[ponygt65]

That's very interesting as a sum of the whole! It was just mentioned that a manufacturing plant in Europe was closed due to some deaths from the mercury that was used to make cfl's. If one looks at the whole cycle from manufacturing to the disposal, cfl's just don't seem to be that great of a deal.

LInk?

I googled it in various ways and found nothing but 'fish' related mercury exposure.

Not saying it's nto true, I'd just like to read the article and couldnt' find it. :shrug:

 

[klrman]

LInk?

I googled it in various ways and found nothing but 'fish' related mercury exposure.

Not saying it's nto true, I'd just like to read the article and couldnt' find it. :shrug:

I searched too and could not find a link either. I heard it briefly on the news up here and it was a plant in Europe but can't remember which country.

 

[ddawg16]

Don't you love how people play with #'s.....while the statement that using CFL's only showed a 12% reduction in 'total' energy use over incandescents....the impression that it gives the listener is they were talking about CFL's alone......

!2% Reduction in my total electric bill? I'll take it.

As for the mecury.....that needs to be taken in proper perspective....how do we know the plant was following all the safety rules....

I saw a report that showed CFL's as a whole put less mecury in the air than incandescents....

Burning coal for eltricity puts trace amounts of mercury in the air....don't forget, Mecury is a 'natural' substance in our enviornment....anyway, the amount of mecury put into the air from the manf of electricity is more than the total for CFL's....this includes the mecury used in the CFL and the mecury created for the electricity....I think the #'s were something like 2.8mg for CFL's and 5mg for Incandescents.